Ancient History & Civilisation




A TWENTY-TWO-YEAR-OLD Sat in the helmsman’s seat and steered the admiral’s flagship southward across the steel blue water of the Hellespont, the narrow channel separating Europe and Asia. As the boat neared its destination, he threw a spear from the ship and plunged it into the ground. Then, wearing a full suit of armor, he was the first man to jump off and step onto the Asian shore. The effect was to mark the land as “spear-won,” territory that the gods had given him to take by force. He had thirty-seven thousand men with him to make good on his claim that spring day in 334 B.C.

About a hundred years later and a thousand miles away, a twenty-nine-year-old led an army. He slogged through some of the most forbidding terrain in the world, the snow-covered Alps, with forty thousand soldiers on foot and eight thousand on horseback. And to top it off—thirty-seven elephants! Only about half of the men would survive that brutal crossing, but on the November day in 218 B.C. when they walked out of the hills, they marched into Roman territory and upended Italy. Seventeen years of war and destruction would follow.

A little more than 150 years later and three hundred miles to the south, a fifty-one-year-old with just five thousand men under his command crossed a river in the northern Italian plain. But that river—really little more than a stream—marked the boundary between his province, where he could legally lead an army, and Italy proper, where he could not. His short journey on a late autumn day signaled the start of nearly thirty years of civil war from one end of Rome’s Mediterranean empire to the other. It was January 12, 49 B.C., by the flawed Roman calendar then in use—about November 24, 50 B.C., by the solar calendar that we use today.

Alexander the Great, in the first anecdote, Hannibal, in the second, and Julius Caesar, in the third, each illustrates a point: history often focuses on a frontier crossing as the start of a great war. Alexander’s Persian expedition began with the crossing of the Hellespont. The Second Punic War began when Hannibal left Spain, marched through southern Gaul, and crossed over the Alps into Italy. The Roman Civil War began when Caesar crossed the Rubicon.

But frontier crossings are an anticlimax. They mark the outbreak of a war, not its cause. Caesar might have said, “The die is cast,” when he traversed the Rubicon, but the game had already begun. Five days earlier the Roman senate had declared Caesar an outlaw, thereby forcing him either to fight or give up his political and military career (and possibly his life). But the collision course between Caesar and the Senate had been obvious for months, if not a year earlier. At least a month before crossing the Rubicon, Caesar had ordered two legions in France to cross the Alps and join him in Italy. When Alexander navigated the Hellespont he was continuing a war begun three years earlier by his father. When Hannibal marched over the Alps he was pursuing a war with Rome that had broken out a year earlier in Spain. And if the ancient sources can be believed, Hannibal had been expecting to fight that war since he was a boy.

Well before they saw the Rubicon and the Alps and the Hellespont, Caesar and Hannibal and Alexander had each decided to go to war. That decision was the most important choice that each of them would ever make. Why did each man choose war?


Alexander: Like Father, Like Son

Alexander’s war on the Persian empire was not a case of self-defense. Neither he nor his country had anything to fear from Persia. As the historian Polybius (ca. 200–118 B.C.) pointed out in ancient times, Alexander fought a war of conquest; in fact, the war was his legacy bequeathed to him by his father, King Philip II. Past Greek successes against the Persians had convinced Philip that the Persian empire was ripe for the taking; there was no doubt about “the splendor of the great prize to which the war promised.”

Brainy and sophisticated, Philip was in touch with the Greek intellectuals of his day. One book might have interested him especially, The Education of Cyrus by the Athenian writer and soldier Xenophon. Xenophon offered a fictionalized but gripping account of how Cyrus, king of a small corner of southwestern Iran, founded the mighty Persian empire by force of arms. Xenophon’s Cyrus was a man of honor and courage who attracted the best men of his day by the force of his character. Whether or not Philip had read the book, he had probably heard of it. And if he had, he surely asked himself, “If Cyrus could do it, why can’t I?”

When it came to ambition, Alexander was his father’s equal. He, too, aimed at conquering the Persian empire. It was a tall order but Alexander was a man of destiny. He was born to fight this war. Like his father, he had the personality of a conqueror, with a passionate conviction of his ability and even of his divinity. Philip hinted in public that the twelve Olympian gods should add him to their ranks. Alexander simply proclaimed himself a god.

Alexander believed that he was descended from the mythical Greek hero Achilles. From childhood on, Alexander identified with him. Branding himself as a second Achilles was a two-edged sword. Achilles was not only Greece’s greatest warrior but also its most selfish. Compared to his own honor, he cared nothing for his country. He chose glory over long life. Achilles loved war and had little interest in hearth and home. For Alexander the parallels would prove all too fitting.

He certainly had a knack for war. His courage and skill stood out in his adolescence. Even before Philip’s death, Alexander showed himself to be a great cavalry commander and a great leader of men. But even if he had been given to timidity or self-doubt, he would have had to squelch the emotions. The consequences of not going to war would have been dire. Alexander had to prove that he was his father’s son. At the age of twenty-two, he also had to show that he could carry out a grown man’s responsibilities.

Alexander’s father, Philip, had survived twenty-three years on the notoriously unstable throne of Macedon by devoting nearly his entire reign to war. His successful expansion abroad underwrote his popularity at home, but in the end, he was assassinated. Philip’s last military act had been to start the long-planned invasion of Persian Anatolia by sending advance forces.

One other thing: Philip had spent practically everything in the Macedonian treasury to pay for his military force. By the time Alexander invaded Persia, Macedon, the richest kingdom in Europe, was broke. Alexander had to fight his way to solvency or face ruin.

Had Alexander not continued the war, he would have been branded a coward and would probably have ended up like his father—dead at the hands of one of his own hawkish countrymen.

Hannibal: The Family Business

Hannibal too sprang from a famous father. Hamilcar Barca emerged as a great general during the First Punic War (264–241 B.C.), a struggle with Rome for control of Sicily. Although Carthage lost the war, Hamilcar won every battle. Afterward, he returned home and achieved even greater success by defeating a savage mercenaries’ revolt (239 B.C.). Under Hamilcar, the Barcas became Carthage’s first family of war.

As good a politician as he was a general, Hamilcar championed the common people in a city dominated by a wealthy elite. He rode a wave of popular support to get a commission to fight in Spain. There, Hamilcar won a new empire, in southern Spain, as a replacement for the empire that Carthage had lost in Sicily. Spain had gold and silver mines and a plentiful supply of soldiers, and Carthage now controlled them. The city regained its power.

Hamilcar brought his nine-year-old son Hannibal with him to Spain. The boy grew up in an armed camp, guided by two brilliant soldiers—his father and his uncle—and gifted with the genetic endowment of his family. Hannibal had two brothers: Hasdrubal and Mago. Hamilcar called his sons “the lion’s brood”—and Hannibal was the alpha male of the pride. Raised to be the consummate commander, he did not disappoint when he reached manhood.

“He was by his very nature truly a marvelous man,” says Polybius of Hannibal, “with a personality suited by its original constitution to carry out anything that lies within human affairs.” He was a man of extremes. His mind was quick and astute but his body was indifferent to pain. He had a sense of humor and a violent temper. He was a man of honor but his critics said he ignored his promises when it suited him and that he had a weakness for money.

Hannibal’s bold and courageous heart yearned to carry out ambitious deeds. Physically imposing, he looked every inch the commander. He was born to be a leader of men, and won the love and loyalty of his troops.

Heroic, expansionist, and blessed by Carthage’s gods—that’s how the Barca family advertised their “brand.” They paid special attention to Melqart, a god of heroism and history. The royal god of Tyre—mother city of Carthage—Melqart made Carthaginians proud of their past. In Spain, Melqart’s temple stood on an island in the Atlantic Ocean, off Gades (modern Cadiz), and symbolized the courage to face the vast unknown. Greeks associated Melqart with their hero, Heracles, and the Barcas advertised the connection on their coins. Displayed in profile, Melqart-Heracles is a tough-looking customer, bull-necked and bearded, with a victory wreath on his head and a club over his shoulder. The reverse side of the coin adds to the image of ferocity by depicting a war elephant.

Hannibal’s ambition shone as brightly as the Barca silver coins. As a young man, Hannibal studied with a Greek tutor. I suspect that of all the heroes of Greece, Alexander the Great was Hannibal’s favorite. As an adult, he certainly imitated the Macedonian—he walked in Alexander’s footsteps by invading a great empire with a small but elite army, and by proclaiming himself a liberator on a divine mission.

But Hannibal was a son of Carthage. Like his country, he was dynamic, expansionist—and hard for us to reconstruct. Rome destroyed Carthage in 146 B.C., in an act of utter annihilation that many scholars today consider to be genocide. Thanks to archaeology, some of Carthage’s material culture has been unearthed, but very little Carthaginian writing survives.

The real Carthage was wealthy, dynamic, and cruel. Its economy rested on commerce and on agricultural wealth. Its armies and navies fought from Spain to Libya, while its seafarers voyaged as far as Ireland and West Africa. Its elite admired Greek culture and couldn’t get enough of it. Its politicians punished defeated generals by crucifixion. Its parents sacrificed their own children as gifts to the angry gods in times of crisis—archaeology demonstrates that the testimony of Greek writers on this point was no myth.

Hannibal was Carthage’s most famous son, but no Carthaginian records about him survive. Our sources for Caesar are excellent and those for Alexander are not bad, but for knowledge of Hannibal, we depend almost exclusively on Greek and Roman writers, especially Polybius and Livy. We simply know less about Hannibal than the other two commanders. Historians’ conclusions about Hannibal contain an element of guesswork.

To return to Hamilcar: he was a loyal citizen of Carthage but he enjoyed almost absolute power in Spain. Although he had political enemies in the Council of Elders that dominated Carthaginian politics, he had far more supporters. The Barca faction believed in national greatness through war and empire. And it was determined to stand up to Rome.

Rome disappointed Carthage by taking Sicily in the First Punic War, but it added humiliation shortly afterward by seizing another Carthaginian island—Sardinia. It was a clear treaty violation but Carthage was too weak to do anything about it at the time. But that changed. Between Spain’s resources and the Barcas’ talent for war, Carthage could say “never again!” Indeed, the Greek and Roman sources claim, the Barcas actively planned a war of revenge.

The story goes that when Hannibal was a boy in 237 B.C., Hamilcar made him swear a solemn oath of eternal enmity toward Rome. Whether this story is true, Hannibal’s actions on the eve of war show how little he trusted Rome.

When Hamilcar died in 228 B.C., his son-in-law, Hasdrubal the Handsome, replaced him. Hasdrubal the Handsome gave Carthaginian Spain a capital at a town he named Carthage (modern-day Cartagena), a great harbor in southeastern Spain. (The Romans later called it New Carthage and, to avoid confusion, so shall we.) If Hasdrubal too planned war with Rome, he was assassinated in 221 before he could act on it. The army in Spain chose a successor by acclamation, and the Carthaginian people confirmed it. Their man was Hannibal, now twenty-six and commander of the Spanish empire that his father had founded. Hannibal quickly displayed his aptitude for war by storming through much of central Spain and expanding Carthage’s empire.

Rome had watched the rise of Carthaginian power in Spain with admiration and fear. Hannibal and his father (and uncle) had put into effect a revolution. When they began, Carthage lay prostrate at the feet of Rome. Now Rome began to fear that it might end up prostrate at the feet of Carthage.

So Rome used the Spanish city of Saguntum (modern Sagunto) as a wedge into Carthaginian Spain. Saguntum had been stirring up Spanish tribes against Hannibal. When the Carthaginians insisted on counterattacking Saguntum, Rome threatened retaliation. Hannibal would not budge. He was, writes Polybius, “young, full of martial ardor, encouraged by the success of his enterprises, and spurred on by his long-standing enmity to Rome.”

Rome claimed that Carthage had violated its treaty obligations by attacking Saguntum, a Roman ally, as guaranteed by a treaty between Rome and Hasdrubal, when he had commanded in Spain. But Carthage challenged Rome on legal grounds while modern scholars question whether Saguntum was Rome’s ally or merely its “friend”—a status that allowed Rome to champion Saguntum without committing to its defense.

By refusing to stand down, Hannibal faced certain war with Rome. The alternative, however, would have meant letting Rome begin expanding in Spain. No one with any knowledge of Roman history could doubt where that would eventually lead: an ever-tightening grip on Carthage’s Spanish empire. The question was, how could Carthage stop it?

One possibility was appeasement. Accept Rome’s superiority, make concessions, and settle down to being a second-rate power in Rome’s orbit. Another possibility was to fight but to stand on the defensive. Let Rome exhaust itself trying to beat Carthaginian armies on their home ground in Spain and probably also in North Africa. With a brilliant general like Hannibal on their side, eventually the Carthaginians would wear out the Romans.

The third possibility, and the one that Hannibal chose, was audacity. He would attack and shock the enemy by invading Italy—an extension of his father Hamilcar’s raids. Hannibal reasoned that his victories in Italy would make Rome’s allies defect to him, and that would force Rome to sue for peace. Never again would Carthage have to worry about Roman aggression. Attack Rome—that was the Barca way.

Like Alexander, then, Hannibal took up with gusto the family business and the military offensive that it demanded.

Caesar: No Chance for Peace

Caesar’s is a more complicated story. Unlike Alexander or Hannibal, Caesar was not the son of a great general. Although he came from an old, patrician Roman family, Caesar was a self-made warrior. Nor had he risen to the top at an early age, like the other two generals. But Caesar did not suffer from an inferiority complex. His family claimed descent from Rome’s legendary ancestor Aeneas, and through Aeneas, the goddess Venus. At age sixteen, Caesar was a priest of Jupiter and, late in life, he allowed the Senate to grant him divine honors.

He was a man of immense ambition. As success mounted upon success, Caesar wanted to become the most powerful Roman of all—or, as he put it bluntly, to be first man in Rome.

A superb soldier, the ambitious Caesar climbed the military ladder steadily. By the time he crossed the Rubicon in 49 B.C., at age fifty, he had gone to the greatest school of all: he had conquered Gaul. It was one of the most brutal, thorough, and profitable victories in Rome’s long history.

Besides being a brilliant general, Caesar was a gifted demagogue and a shrewd politician. He planned to leverage his success in Gaul into further power and honor in Rome and then another great command, this time against the Parthians (an Iranian empire). But the many political enemies whom he had made in his meteoric rise had no intention of letting that happen. As he piled success upon success in Gaul, as he acquired gigantic wealth, power, and military force, a rising political chorus in Rome called for his head.

Caesar ran the greatest risks of all by not going to war. If he had kept the peace, he would have had to give up his office as governor of Gaul, the province that he had conquered for Rome. He would have had to return to Italy as a private citizen, where prominent senators said they would immediately prosecute him for various illegalities in his prior career. Caesar could expect that, as in a recent trial at Rome, his political enemy Pompey would have the courthouse surrounded by soldiers, in order to “persuade” the jurors how to vote. The result would almost certainly be condemnation, with exile or execution to follow. It would be the end of Caesar’s public career and possibly his life. By going to war, Caesar had a better chance of achieving his long-term ambition of supreme power.

Caesar’s rise took place against the background of the crisis of the Roman republic. The great city that had conquered an empire was in poor shape. By the time Caesar crossed the Rubicon, Rome had witnessed ninety years of intermittent turmoil on the home front, including riots and assassinations (133–121 B.C.), an allied revolt (90–88 B.C.), a slave war (73–71 B.C.), and a debtors’ rebellion (63 B.C.). Worst of all was a civil war (86–82 B.C.) that made it clear that a determined general with a veteran army could trample on the political power of the Roman senate. A longtime rivalry between the Roman generals Marius and Sulla ended with Sulla conquering his own country, massacring his enemies, and becoming dictator for life. His early death (79 B.C.) allowed the Senate to reestablish its authority. When Caesar crossed the Rubicon, Rome had been a republic again for thirty years, but generals like Pompey and Caesar cast a shadow on its freedom.

Like Caesar, Pompey too insisted on being the first man in Rome. Born in 106 B.C., he made his name as a general while still in his twenties by fighting for Sulla in the civil war. Sulla called him Pompeius Magnus, “Pompey the Great.” Another, less flattering nickname also dated to this era: “the teenage butcher,” probably referring to his slaughter of captured opponents.

The rest of Pompey’s military career played out over a vast canvas for nearly fifteen years between 76 and 63 B.C. First he ground down the Roman rebel Sertorius during a five-year-long struggle in Spain. Then Pompey took credit for beating the rebel gladiator Spartacus in Italy (another general, Marcus Licinius Crassus, did most of the work). Finally there came a series of spectacular victories in the eastern Mediterranean: over the pirates, whom he put out of business; over the rebel Mithradates, whom he drove to suicide; and over a swath of territory extending from the Black Sea to the Jordan River, all of which he put under Rome’s control.

Pompey spent the years between 63 and 49 B.C. back in Rome. He was more than happy to run roughshod over the Senate’s powers during that period and to dominate politics through a series of backroom deals with Caesar and Crassus. But Crassus fell in battle (53 B.C.) and Caesar won immortality in Gaul.

Pompey could not bear the thought of Caesar coming back from Gaul and dominating Roman politics, so he discovered the virtues of Rome’s good old republican system of government. He decided to ride to the Senate’s rescue and take up arms on its behalf. The senators did not trust him but they needed his military skill.

“The Republic is not the question at issue,” as Cicero would soon write. “The struggle is over who is to be king.” In 49 B.C., Pompey and the Senate made uneasy allies. A ruthless enemy like Caesar could exploit their mutual suspicion.

Unlike Alexander or Hannibal, Caesar did not fight the war he wanted; he would have preferred to lead an army against Parthia rather than against fellow Romans. But he didn’t shrink from civil war when it became necessary.

Caesar’s domestic enemies treated him unfairly, but by crossing the Rubicon, Caesar did worse: he engaged in treason. He was a rebel general attacking the legitimate government of his country. A more modest man would have spared his country.

In his Civil War, Caesar offered two justifications for his action. He told his soldiers, in a public meeting, that he was fighting to defend the power of Rome’s tribunes—the representatives of the people. Caesar also emphasized the matter of rank (dignitas in Latin). The issue, Caesar told his soldiers in a public meeting, was the “reputation and rank” of their commander. To Pompey, Caesar wrote that he had always considered “the rank of the republic” more important than life, and the rank in question was “a benefit granted to me [Caesar] by the Roman people”—that is, his command in Gaul. Men noticed what Caesar was saying. As Cicero wrote to a confidant, “He [Caesar] says he is doing everything for the sake of rank.” To the Romans, rank was a core value, the way freedom or security or community is a core value to modern electorates. By defending himself, Caesar claimed to be defending the Roman way of life.

Or so he said. It is hard not to think that “the liberty of the people,” “the sacrosanct status of the tribunes,” “the rank of the nobles,” to him were all spelled “Caesar.”


So much for the reasons why Alexander, Hannibal, and Caesar each went to war. How did they plan to win? This is no small question because there were excellent reasons why each of them should have lost.

They shared a similarly bleak strategic situation at the outset. Each man was about to invade a country whose military force outnumbered him in manpower and money. Each man faced an enemy who had command of the sea. Hannibal and Caesar both lacked navies; Alexander’s navy could not compete with his enemy’s.

Yet each man expected victory. Each one’s story was a classic case of something that has happened again and again in history. A ruthless general with a hardened, elite, and small army tries to knock out a flabby giant. Sometimes it works: Hernando Cortés, for instance, began with only six hundred men when he marched on the Aztecs in 1519; by 1521 he had conquered Mexico. Sometimes it fails, as when Robert E. Lee invaded Pennsylvania in 1863 and lost at Gettysburg or when Hitler invaded Russia in 1941 and later lost at Stalingrad.

Our three commanders shared certain advantages. In spite of relative deficiencies in money or manpower, they had a distinct advantage in infrastructure. They all led experienced armies with a record of dominance in pitched battle—that is, a formal engagement planned beforehand and fought on chosen ground. Each was a constant campaigner, a master of mobility who pushed his army forward. All were great leaders, gifted with the ability to inspire the troops and shrewd enough to keep a steady stream of material rewards flowing to them. They had outstanding moral and physical qualities, such as courage, patience, vigor, and stamina, but their intellectual qualities were even more important. Each man combined a superior intellect with a decisive and resolute will. They lacked nothing in audacity. All were bold; none was risk-averse. Foresight, aptitude, and sheer brainpower are essential to a great commander; good judgment, especially in a crisis, is the most important quality of all. Each had a passionate conviction of his destiny and ability, not to say his divinity.

Each of the three commanders had a rare combination of instinct and arrogance. Each had the good judgment to size up his enemy correctly. Great men think they know their enemy and they have contempt for him. And one of the things that makes them great is that they are usually right. Alexander, for example, knew the Persians could not resist battle, just as Hannibal knew that neither could the Romans. Caesar knew that Pompey could not seize the day.

All three men were gifted with strategic vision. Each had a plan for victory: a blueprint for translating battlefield success into reality. Yet each man was an improviser and an opportunist, quick to take advantage of any possibility that happened to open.

For Hannibal, the argument boiled down, we might suspect, to science; to Caesar, character; and to Alexander, culture. Alexander had learned from his tutor, the philosopher Aristotle, that Persians were barbarians, without a Greek’s love of freedom or the willingness to stand steadfastly and die for it. “The enemy would have won that day, if they had a general,” is Caesar’s blistering appraisal of Pompey’s leadership on a day of hard fighting in 48 B.C. Hannibal knew that, with his ability to combine infantry and cavalry, to maneuver, and to employ deceit, he was the master of military science—he was an artist of the battlefield; by comparison, the Romans were mere hammer drivers.

Alexander: Looking for a Fight

Alexander led one of history’s most victorious armies and one of its most versatile. He had inherited it from his father, Philip, king of Macedon and founder of its military greatness. Philip was brilliant. By applying the latest advances in Greek military technology to Macedon’s backward army, he forged a disciplined, professional, year-round force.

Macedon, with its plains and horses, was cavalry country, and Philip raised cavalry to new importance. The Macedonian heavy cavalry, now known as the Companion Cavalry, benefited from new recruitment and training, new weapons, new tactics, and new doctrine. The sons of the aristocracy went to court as teenagers and were trained as cavalrymen. They were outfitted with extra-long lances that gave them added reach compared with their enemies. They learned to fight in a wedge-shaped formation that was both more maneuverable than an in-line formation and more effective at penetrating the enemy line. Their doctrine was cunning aggression: they scanned the enemy line for a gap and then shot through it with murderous intensity. In short, the new Macedonian cavalry excelled at shock attack.

Alexander invaded Persian territory with eighteen hundred Companion Cavalry. They were organized in eight squadrons of which the Royal Squadron was the most elite; Alexander himself rode in the Royal Squadron’s lead. Although small in number, the Companion Cavalry was one of the most effective units of horsemen in military history.

The cavalry spearheaded Macedonian victories but it couldn’t have done so without the help of the other units in the Macedonian army, which Philip also revolutionized. Macedonian heavy infantrymen fought in a closely packed unit, the phalanx, like earlier Greek infantrymen. But they carried extra-long pikes to keep the enemy at a distance and they trained year-round. An elite infantry corps, known as the hypaspists, linked up the cavalry and infantry. Their job was to minimize the gap that inevitably opened when the cavalry sped ahead of the slower-marching infantry. Specialized units of slingers, archers, and javelin men raised the army’s ability to meet all challenges. So did Philip’s mastery of the technology of siegecraft, which he brought to a level of efficiency unseen since centuries before in the Near East.

A Macedonian battle represented an orchestrated balance of cavalry and infantry, with specialized units also playing a part. The standard tactic was to place the infantry in the center of the line and the cavalry on the flanks, with the best cavalry on the right wing. Typically, the Macedonian heavy infantrymen would first hold the enemy and try to create a weak spot in its line. The cavalry would then spring into action and rip open the enemy formation. Light-armed infantry, specially trained to dart among horses, helped the cavalry along. Then the heavy infantry would follow and finish the job.

Although the core of his army was Macedonian, Alexander’s soldiers also included a number of reliable allies. Cavalry from Thessaly (in central Greece), Agrianian javelin-men from the mountains of what is today southern Serbia, and Cretan slingers and archers stood out. So did the mercenaries, who were employed in large numbers.

Alexander had a superb group of general officers to rely on, led by Philip’s marshals. Although the young king surely itched to replace them with his own men, he was too shrewd to do so. He knew that Philip’s men represented Macedon’s proud and close-knit nobility. They had the troops’ support and besides, he had no one to match their skill or experience. Alexander had a fingertip feel for political as well as military reality. So he kept Philip’s generals. Meanwhile, Alexander bonded with his soldiers by displaying strategic insight, courage in battle, and limitless self-confidence.

Between the leaders and the men they led, Alexander’s was one of history’s greatest armies. If the Persians decided to fight conventional battles, then the Macedonians had a real chance of winning, despite massive inferiority in money and manpower. But if the Persians chose a different strategy, one based on a combination of unconventional warfare on land and a naval offensive at sea, then they might have rendered Alexander’s army a splendid but irrelevant machine. Even great armies can lose wars if the enemy is cunning, determined, and resourceful.

The Persians ruled the largest empire in history to that date, stretching from Central Asia to Egypt, and including perhaps one-fifth of the world’s population. With their huge sources of military manpower, the Persians substantially outnumbered the Macedonians. Great horsemen, the Persians had excellent cavalry and they made up for their weakness in infantry by hiring first-class Greek mercenary infantrymen. But their inexperience, lack of trusted generals, and—in the case of the cavalry—inferior equipment put the Persians at a great disadvantage against the Macedonians in battle.

The Greeks called Persia’s emperor the “Great King.” The adjective “good” probably better fit the current occupant of the throne, Darius III. He was a fine battlefield commander and an excellent military organizer. He was a shrewd political operator and a cunning diplomat. But he lacked experience and legitimacy: like Alexander, he was a new king (his reign began in 336 B.C.), but unlike him, Darius was neither the heir to the throne nor a king’s son. Born Codomanus, he was a fine military man but he did not have his eye on the throne. Darius became king only after the long-reigning Persian monarch Artaxerxes III (r. 358–338) and his son Arses (r. 338–336) had each been murdered by his chief minister. Darius was their distant cousin. Many Persians looked on Darius as a usurper and gave him less than their full support. Alexander had a seasoned corps of generals committed to a common purpose, but Darius suffered from divided and inexperienced advisors.

When it came to size and resources, the Persian empire experienced a real difference between reality and appearance. Many of the provinces at either end of the empire were barely under Persian control. Egypt, for example, was perpetually in revolt, most recently in the 340s; the satraps (provincial governors) of Anatolia mounted a revolt in the 360s that smoldered until the 340s; the provinces of Central and South Asia were more or less independent.

Still, in spite of Persia’s disadvantages, a brilliant leader with a sure touch and a dollop of luck could have defeated Alexander. Unfortunately, Darius, although courageous, intelligent, and an excellent organizer, lacked Alexander’s skill and experience as a field commander.

Still, Darius knew enough to turn to Persia’s tried-and-true policy against Greek invasion: a naval counteroffensive. This strategy had stopped Sparta in 395 B.C. after it invaded Anatolia. It looked promising now in 334, when Macedon’s navy was small and unreliable, consisting almost entirely of Athenian allies, although most Athenians resented Macedonian hegemony. Persia’s navy was big and trustworthy. If it made a serious push across the Aegean Sea, Persia could raise a rebellion in Alexander’s rear, in the Greek city-states. The Persian navy might defeat Alexander while his invasion was just beginning.

Hannibal: Force and Fraud

Few generals have ever approached the battlefield as well armed in force and fraud as Hannibal. Few have ever pulled off greater feats of mobility. As with the wigs and disguises that he wore to foil assassins, Hannibal was full of tricks. But he was also a deadly battlefield puncher.

Hannibal’s army consisted of a varied mix of men and abilities. Indeed, one of his greatest achievements was turning them into a cohesive whole.

The Roman army in Hannibal’s day consisted of citizen-soldiers. Ordinary Roman males, most of them farmers, served their country as soldiers. Fighting beside them were soldiers from allied cities in Italy, most of whom were also citizen-soldiers.

Carthage’s army was totally different. Only some of the officers were Carthaginian; the troops represented other nationalities. Some were mercenaries but most had been recruited from the various peoples in North Africa and Spain under Carthaginian rule. Some were inexperienced but others had soldiered long enough to be considered professionals. Hannibal’s best troops were North Africans—Libyans and Numidians (today, Algerians). Next came the Spaniards, to whom he soon added northern Italian Celts. As infantrymen, the best of them—the Libyans—rivaled Rome’s famed legionaries, but they could not match their numbers. What gave Hannibal an edge was his horsemen and his ability to maneuver them. He used cavalry more successfully than any general since Alexander, a century earlier.

Hannibal’s father, Hamilcar Barca, had learned how to win battles from Greek military experts. His method was to hold the enemy in the center while enveloping him on the wings and even the rear. It was not an easy maneuver to carry out but when accomplished it could be devastating. Hannibal, who learned these tactics from his father, carried them out brilliantly. Hannibal commanded both heavy and light cavalry. Together, these infantry could run rings around Roman cavalry. Hannibal’s cavalrymen were trained to fight in tandem with his infantrymen. Combined, they represented a deadly one-two punch. Because they were professionals, Hannibal’s men had the training to carry out maneuvers that Rome’s citizen-soldiers could only dream of. Meanwhile, his elephants would shield Hannibal’s infantry and terrify the enemy. The result would be state-of-the-art military science.

Hannibal’s army had certain advantages of command and experience. He had a fine corps of supporting generals. In Italy officers like Maharbal, son of Himilco; Hanno, son of Bomilcar; and one Hasdrubal (not Hannibal’s brother) would rip Roman armies to pieces. But Hannibal’s generals did not do well on their own without his guiding hand, starting with his two brothers, Mago and Hasdrubal. The one exception, Mottones, Hannibal’s hand-picked cavalry commander in Sicily, shone in battle but fell afoul of Carthaginian political in-fighting. He turned traitor and became a Roman citizen—and general!

As for the Carthaginian army, Polybius describes Hannibal’s men thus: they “had been trained in actual warfare constantly from their earliest youth, they had a general who had been brought up together with them and was accustomed from childhood to operations in the field, they had won many battles in Spain . . . . ”

Not that Hannibal could afford to ignore the deadly cohesion and steadfastness of the Roman legions! Unlike most of Rome’s opponents, however, he had a chance of beating Rome. A tactical giant, Hannibal reckoned that his superior generalship could defeat the Romans in battle and cause them enormous casualties. But he would have to move with devastating speed and overwhelming force. Otherwise, he might end up like Pyrrhus.

King Pyrrhus of Epirus invaded southern Italy in 280 B.C. A charismatic general like Hannibal, Pyrrhus too had a small but experienced army complete with cavalry and elephants. Unlike Hannibal, he even had many Italian allies. Pyrrhus won two major pitched battles against Rome but suffered such severe losses as to render them “Pyrrhic victories”—the term we still use today. More important, Rome refused to concede. Rome’s central Italian allies held steadfast and provided new troops, but Pyrrhus’s manpower was running out.

Furthermore, Rome won the support of a key ally from outside Italy. Ironically, it was Carthage that feared that Pyrrhus would invade its territory in Sicily. That indeed happened, but Pyrrhus did no better in Sicily than in Italy. Meanwhile, Rome pummeled his Italian allies, so Pyrrhus returned to help them, only to be defeated in battle. In 275, Pyrrhus went home, having accomplished nothing.

Hannibal risked a similar fate. In fact, he risked worse, because in Pyrrhus’s day, Rome had no fleet. Now it had a great navy, which meant that it could counterattack in Spain. Carthage did not have much of a navy of its own, having lost its fleet in the First Punic War.

In 218 B.C., Rome had 220 warships, while Carthage had only one hundred. But the numbers tell only part of the story. Since winning the First Punic War, Rome’s sailors had developed expertise and guts. Carthage’s sailors had stagnated. In 218 Carthage needed not only more ships but also a new and bolder naval culture. Its admirals included no Hannibals.

Geography was another problem. Rome controlled the vital ports in Sicily and Sardinia. Ancient navies needed to make frequent stops on shore, so whoever controlled the harbors of these central Mediterranean islands controlled the sea-lanes.

For all these reasons, Hannibal could not ship his forces to Italy. He had no other invasion route but a grueling, thousand-mile overland march from southern Spain to northern Italy. And that might cost him vital manpower.

The key to Rome’s strength was its confederacy. Between 350 and 270 B.C. Rome had conquered all of the communities of Italy south of the Po and Rubicon rivers. It was a large area to control and Rome used various strategies to do so, from annexing territory, building roads, and planting colonies to intervening as needed in order to install friendly politicians in power.

But two Roman policies stand out in importance. First, Rome turned itself into a population giant by granting Roman citizenship to many of the conquered peoples. By 225 B.C. Rome’s population, in the city of Rome and Roman territory all over Italy, was close to one million free people, of whom 300,000 were adult males and so therefore, liable for military service. Second, Rome required its allies to contribute soldiers to the Roman army. In 225, allied troops amounted to 460,000 men. So Rome had a total of 760,000 potential soldiers.

This was a staggering number, especially considering Hannibal’s forces, about 60,000 men when he first left Spain but a mere 26,000 men when he reached northern Italy after his devastating march. How, then, did he plan to defeat Rome?

The answer was to crack the Roman confederacy. Hannibal planned to shock Italy by handing Rome such big defeats in battle that the allies would start defecting to him, first in a trickle and then a flood. Their actions would add to Hannibal’s manpower and subtract from Rome’s. Rome might hold out at first, but eventually Hannibal would win away so many of Rome’s allied troops that Rome would come to the bargaining table.

To make his task slightly easier, Hannibal didn’t plan to destroy Rome, merely to defang it. He was fighting, he said, only for “honor and empire.” He wanted to protect Carthage’s empire in Spain and to get back Sardinia, and probably Sicily as well.

For Hannibal, then, victory depended on two things: battle victories and allied defections. Could he achieve his goal?

Polybius didn’t think so. The historian criticized Hannibal for going to war on emotional grounds rather than rational analysis: Hannibal was “wholly under the influence of unreasoning and violent anger.” Rome was just too strong and Hannibal should never have invaded Italy, according to Polybius.

Polybius is a formidable historian, but he doesn’t give audacity its due. It would be fairer to say this: Hannibal had a well-thought-out if highly risky plan. It began with a long and dangerous march followed by a rapid series of hammer blows to Rome’s homeland, so hard and fast that Rome’s Italian confederacy would crack. It also called for diplomatic finesse in dealing with Rome’s Italian allies and political shrewdness in managing the home government in Carthage.

Not since Alexander had any general displayed so much offensive ability. If anyone could do it, Hannibal could, but was Rome too strong?

Caesar: Speed Kills

As he made his plans on the far side of the Rubicon, Caesar might have calculated his military strengths and weaknesses. His greatest strength by far was his army. Caesar’s army was not merely good, it was his. Eight years in Gaul had tied the men to him by blood and iron and faith. The army believed in Caesar.

He, in turn, played them like a lute. He overlooked their lapses and foibles but came down hard on deserters. He never called them “soldiers” but always “fellow soldiers.” After a massacre in Gaul, he swore not to cut his hair or beard until he had avenged the dead—and, as everyone knew, he was vain about his looks, so it was a sacrifice indeed.

Caesar’s army worshiped his brains, his courage, his charity, and his charisma. Thirty thousand fighting men saw him as their captain, their patron, their leader, and even their father. In Gaul he gave them victory and profit. The men never lacked for material rewards: Caesar saw to that. Now, he promised them the first rank in the Roman state.

True, civil war offered fewer sources of loot than foreign conflict, and that would generate tension. Yet Caesar’s political skills would keep his men happy, and besides, civil war offered the thrill of the illicit, the knowledge that every man in his army had made himself an outlaw once he crossed the Rubicon. The prospect of victory or death wove extraordinary ties between leader and led. It was, in short, a love story.

Caesar’s forces at the Rubicon were small in number but reinforcements were on the way. Meanwhile, he had the men of the Thirteenth Legion. Veterans of Gaul, they were experienced and self-controlled. They knew how to infiltrate a town and then suddenly make their presence known. One legion—five thousand men—was big enough to lay siege to a small city, and Caesar’s army was expert in sieges. Once his numbers increased, they could do the same to big cities.

Nor was there any doubt about their ability to move fast. Alexander and Hannibal were speedy but Caesar was quicksilver—an athlete of the battlefield. Rarely has a general understood better that speed kills. Neither did Caesar lack stamina. His army combined the speed of a cheetah with the endurance of an ant.

Once he had more soldiers, Caesar would relish meeting the enemy in battle. He might have guessed, however, that Pompey would not want to risk his men against Caesar’s veterans. More likely, Caesar would have to outrun and outmaneuver Pompey, and catch him in a town that he could besiege or maybe even take by storm.

Caesar knew Pompey personally and seems to have had genuine affection for him, but Caesar had no doubt about his own superiority as a general. Whether he thought that Pompey had lost his skill or that he had never had it, Caesar was convinced that he was better.

It didn’t matter. Whatever Pompey might have been able to do, he suffered one big disadvantage: he lacked supreme command. Instead, he shared command with several leading senators. His army lacked the unity at the top that victory usually requires. Caesar, the undisputed chief, did not have to wrestle with other generals. He was not a committee chairman but a leader.

Balanced against this advantage was a big military disadvantage: Caesar had no navy. If he could not beat his enemies in Italy, they could escape by ship and live to fight another day. And perhaps Pompey was not quite so inferior as Caesar might have thought. It was all the more reason for Caesar to move with speed and decisiveness.

Caesar was enough of a realist to know that he would probably not catch Pompey in a decisive battle in Italy. To win the war, Caesar would have to overcome his weakness at sea, transport his army abroad, and force Pompey into a do-or-die battle. Could he do it? That would be Caesar’s greatest test.

Targets Hard and Soft

When Alexander and Caesar each launched their wars, the enemy—the Persian empire or the Roman republic—had already been weakened by decades of regional rebellions and civil war. Mercenaries and adventurers in force had already crisscrossed the Aegean Sea for years when Alexander invaded. Caesar was not the first rebel general to march on Rome. Neither Darius’s Persia nor Pompey’s Rome offered a united front to the invader; each suffered from factionalism.

By contrast, the Roman republic attacked by Hannibal stood relatively united. Rome’s Italian confederacy was vulnerable in northern Italy, where the Celts had only recently lost their freedom to Rome and southern Italy too had its share of independistas. But the core of Rome’s Italian confederacy in central Italy was rock solid. To win the war, Hannibal had to break that rock. If that was not impossible, neither was it easy.

So Hannibal faced a tougher job than either Caesar or Alexander did. Domestic politics did not make his task easier. Hannibal was not a king or a dictator but a general of the Carthaginian state. Although Spain gave him a power base, he would need support from Carthage unless he defeated Rome very rapidly. And that support was not guaranteed.

Most Carthaginians were eager to fight their hated Roman enemy, but that doesn’t mean they supported Hannibal’s war plans. Some disagreed with his strategy, while others distrusted him or disliked the Barcas. And Hannibal had last seen Carthage when he was nine years old. His knowledge of domestic politics could hardly match his familiarity with the field of arms.

The other two commanders also faced problems on the home front. Alexander was a king loathed by most of the Greek city-states that were, in theory, his allies. Many of Alexander’s Greek allies were itching to rebel and join Persia. Caesar was no king but a rebel provincial general against lawful authority; he lacked legitimacy. Even if Caesar conquered Italy, he had no fleet to pry open the sea-lanes needed to get grain supplies through; if Pompey took to the sea, he could starve Italy.

All in all, Hannibal had the most difficult task. To crack Rome’s Central Italian confederacy would take the application of great resources in infrastructure to precisely the right point. Hannibal had to procure those resources from the Carthaginian government and he had to direct them against the proper target. That would require a grasp both of strategy and of politics. The war would prove if Hannibal had it.


All three men fought wars with a strongly political dimension. Like most generals today, none had the luxury of following military logic alone. Each had to take politics into account as well.

Alexander: Politician and General

Alexander’s march into the Persian empire was not merely an invasion route but a form of information warfare, aimed at two audiences: the Persian army and Greek public opinion. His message to Persia was that he was coming in force. For two years, the Macedonian army in Anatolia had consisted of a 10,000-man advance force. Now, in 334, nearly 50,000 Macedonians—an additional 32,000 infantry and 5,000 cavalry—had invaded, along with a fleet of 160 warships and numerous transports. To the Greeks, Alexander presented his expedition as revenge—he marketed it as a Panhellenic crusade to avenge the Persians’ invasion of 480 B.C. That was long ago but most Greeks still thought of the Persians as “the barbarian,” as their ancestors had.

But Alexander had to shore up weak support—indeed, the threat of rebellion—from his Greek rear, including the unreliable Athenian navy. He had to show that he was pro-Greek and that any Greeks who supported Persia would be dealt with severely. He did that by a combination of branding and brutal reprisals.

In order to emphasize the theme of Greek revenge, Alexander led the Macedonian army eastward toward the Hellespont on about the same route that the Persian king Xerxes had followed when he marched westward in his doomed invasion of Greece in 480 B.C. Alexander crossed the Hellespont from Sestos to Abydos, the very place where Xerxes had bridged the channel (they went by ship) in the opposite direction. While crossing the Hellespont, Alexander made sacrifices to the gods and poured a libation to the water, in contrast with Xerxes, who had his men whip the Hellespont and toss chains in it to “punish” the water for a destructive storm, acts that the Greeks considered impious.

When he landed near Abydos, Alexander strode onto the shore of Asia in full armor. He had already thrown a spear from the ship: a sign, as he later put it, that he considered the Persian empire a spear-won land from the gods. For good measure, Alexander went to the nearby city of Troy or, rather, Ilion, the Greek city built on the site of Troy. Xerxes had made a similar pilgrimage there in 480, and Alexander could do no less.

Having waged a propaganda campaign to demonstrate his devotion to the cause of Greece, Alexander now returned to the main purpose of his trip to Anatolia: he rejoined his army.

Alexander invaded the Persian empire in 334 B.C. with a clear war plan but an open-ended goal. At a minimum he wanted to conquer western Anatolia (modern Turkey) and add it to his kingdom. At a maximum—well, there is reason to think that Philip had aimed at conquering the entire Persian empire in all of its vastness. This included both Persia’s other holdings in Western Asia—Syria, Palestine, Egypt, and Mesopotamia—and lands lying farther eastward—the Iranian plateau and all or part of modern Kazakhstan, Afghanistan, Tajikistan, Uzbekistan, Pakistan, and northwestern India. It was a huge ambition, and to some it would probably have seemed like a mythological tale. No one could rule an empire this big without becoming an absolute monarch; Alexander’s advisors knew this, and many of them eventually recoiled in horror from the prospect. But it probably seemed unlikely at first, since the Persian empire was no pushover. Although it had demonstrated military weakness in recent years, Persia still had huge advantages in money, manpower, ships, and local knowledge.

Each step in Alexander’s campaign was in itself a tall order. Take Anatolia. To conquer it, Alexander had to keep the Persian navy from opening a second front in Greece as well as defeat the Persian army in Anatolia. He also had to win allies and find food for his men. Last but not least, he had to raise money, because war is expensive, and the Macedonian treasury was empty.

In 334 B.C. Alexander was twenty-two and had sat on the throne for only two years. Yet he was already an experienced field commander. At age sixteen, Philip made him regent of Macedonia, and Alexander led a rapid expedition to Thrace that put down a rebellion and turned a city into a Macedonian military outpost called Alexandropolis. At age eighteen, under Philip’s supervision, Alexander led the Macedonian cavalry on the war-winning charge that conquered Greece at the Battle of Chaeronea (338 B.C.). At twenty, he became king. In the next two years as commander-in-chief of the Macedonian army, he marched his armies a thousand miles, suppressed rebellions in Greece and the Balkans, and destroyed Thebes, Greece’s single most powerful land power. He also extended his empire’s northern frontier to the Danube River, won a series of victories on his own without the help of Philip’s best generals, and executed both precisely planned operations and brilliant improvisations. Alexander demonstrated other skills as well, such as his mastery of combined-arms operations, in which he used cavalry and light-armed and heavy-armed infantry. He showed himself able to scramble when needed, by sizing up both enemy and terrain on the spot and issuing precisely the right orders. He was very inventive. On one occasion, he had his men cut steps up the cliff face of a mountain, and on another occasion, he ordered them to throw together a scratch fleet to cross the Danube. His most creative manuever of all was history’s first recorded use of field artillery.

Alexander had earned the love of his soldiers. He also earned the fear of Macedon’s Greek and Balkan allies but he didn’t trust them. Nowadays, the province of Macedonia (not to be confused with the independent country to the north) is an integral part of Greece, but in Alexander’s era, many Greeks looked on Macedonians as savages, and would have been glad to revolt, given a chance. The Persian navy represented that chance. To discourage the Greeks, Alexander left 13,500 soldiers (27 percent—i.e., more than one quarter—of his total forces) in Macedonia when he invaded Persia. Their job was to be ready to invade any Greek city-state that joined the Persians.

Every major city-state on the Greek mainland except Sparta had joined Alexander’s coalition. Sparta stubbornly held out. Its great days were behind it, however, and it was now mainly a small and out-of-the way place with a glorious name. Even if its refusal smarted, Sparta was not worth the trouble to conquer.

Alexander also planned a political response to the threatened Persian naval offensive. As he drove the Persians out of the Greek cities of Anatolia, he advertised himself as a liberator for all Greeks. But he also showed himself to be a killer: in his first battle he executed most Greek mercenaries caught fighting for Persia, which was a brutal act, considering that captured mercenaries were usually easily encouraged to change sides. He wanted to make a political more than a military point in order to discourage other Greeks from fighting for Persia.

Hannibal: The Diplomat

When he marched against Rome in 218 B.C., Hannibal was already an accomplished commander. He had spent two years conquering hostile Spanish tribes and then turning to Rome’s Spanish ally, Saguntum. He laid siege to the city and took it after eight months. When Rome declared war, Hannibal was ready with a daring plan: an overland march across the Pyrenees and the hostile territory of southern France and the Alps—with elephants, no less.

Hannibal had crushed his Spanish enemies and earned the love of his men. He offered military prowess and leadership skill, to which he added public relations. He used religion deftly to appeal to the various Celtic peoples in his army. Unlike Alexander, Hannibal never claimed to be a god, but he avowed divine patronage. He branded himself as a new Hercules. Before leaving New Carthage, he made a special trip to Gades to pray at the shrine of Melqart, the Punic Hercules. In the Alps, there was talk of a god—plausibly, Hercules—leading Hannibal through the mountains. On the march through northern Spain, Hannibal reported a dream of a young man sent by the king of the gods to guide him to Italy and to ravage its land like a giant serpent.

In spite of that serpent, Hannibal was a diplomat who planned to win the support of potential allies in enemy territory. Rome had conquered the peoples of central and southern Italy one by one. Many of them chafed under its rule. But a bigger problem was Rome’s fragile control of the Celts, whose tribes comprised the majority of the population of the Po valley and most of today’s northern Italy (including Piedmont, Lombardy, the Veneto, and Emilia-Romagna). They had launched a great rebellion between 225 and 222 B.C. and were still simmering in discontent after defeat by Rome. Before setting out on his expedition, Hannibal sent ambassadors to the Celts and won promises of support from some tribes.

Meanwhile, in central and southern Italy, the population did not express anti-Roman sentiments as openly, but these regions too were rich in subterranean feelings of resentment. Hannibal planned to raise them up. He would tell Italians that he had come not as a conqueror but a liberator. After each of his victories he enslaved Romans but freed any Italians that his men had captured.

Hannibal’s comparison of himself to Hercules—Heracles to Greeks—played well in southern Italy. Pyrrhus too had likened himself to Heracles, and so had the greatest Greek conqueror of all, Alexander.

Hannibal had two other political audiences to think of, one in Spain and the other in North Africa. Some Spanish tribes still smarted under Carthaginian rule; should Hannibal falter in Italy, the news might spark their rebellion. When he marched to Italy, therefore, he left soldiers, ships, and elephants behind in Spain under the command of his brother Hasdrubal to keep the Spaniards in line.

Even more important for Hannibal was the politics of Carthage’s government. Hannibal protected Carthage by sending sixteen thousand soldiers from Spain to North Africa when he left for Italy. Carthage had supported Hannibal when Rome demanded his head, after the siege of Saguntum. The city had fought rather than hand over Hannibal, but they also wanted to keep Spain—and knew they had to protect Hannibal to do so. When it came to the Italian campaign, they might have felt differently.

As at Rome, so in Carthage a council of elders or senate played a leading role in the government. Its members had mixed feelings about Hannibal’s war. On the one hand, they hated Rome, but on the other hand, many of them distrusted Hannibal. The Barca family had won Carthage a lucrative province in Spain but had also won itself a power base. If Hannibal now added Italy to his sphere of influence, he would tower over Carthage. Political titans always make councils of elders nervous. “Safety in numbers” is usually their motto.

So the Carthaginian senate supported Hannibal but not in every particular. Many senators had their own agenda—winning back the lost colonies in Sicily and Sardinia. They saw the war in Italy as a means to that end. Should Hannibal stumble there, they were ready to open new fronts in the islands and to turn to new commanders—preferably ones with lesser political ambitions.

To win the war in Italy, therefore, Hannibal had to be far more than a great general. He had also to be a first-class diplomat, an able propagandist, and a cunning domestic politician.

Caesar: Shock and Awe Commander

What the Barca family had built in Spain, Caesar achieved in Gaul: conquest of a rich province that was all but his own property. Unlike Hannibal, however, who had left Carthage for good at the age of nine to follow his father to Spain, Caesar had built a career in Rome before going to Gaul: he was already a veteran politician when, in his forties, he became a conqueror. Caesar’s actions both before and after crossing the Rubicon demonstrate his mastery of the art of being a political general—of being, in short, Caesar.

Caesar used his victory in Gaul well. To advertise his success he wrote a literary classic, The Gallic War, in which he branded himself as a military giant. From its famous opening—“All Gaul is divided into three parts”—Caesar proclaimed to the Roman people his military and political skill; after all, “divide and conquer” was the oldest maxim of Roman warfare. The book drove home the power of Caesar’s military. It was quick, efficient, ruthless, and utterly ready to commit acts of terror: Caesar was said to have been responsible for a million deaths in the conquest of Gaul and a million more enslaved, many of them civilians.

While in Gaul, Caesar kept a finger on the pulse of politics in Rome. Gaul was a vast province, big enough to allow Caesar to spend his winters in Ravenna in northern Italy, just 200 miles from Rome. In 49 B.C., northern Italy was not considered Roman territory; it was a foreign province, under the rule of a Roman governor—Caesar. Northern Italy was called Cisalpine Gaul, “Gaul on this side [the south side] of the Alps,” and it was part of Caesar’s Gallic command. While wintering in Ravenna, Caesar commanded one legion. His other legions were north of the Alps, but three of them were poised to reach him quickly.

Having made his name as a populist before going to Gaul, Caesar continued the tradition by sending loot home to fund public works projects. He offered the Roman people a program of welfare benefits, which made him more popular than the grandees in the Roman senate, who jealously guarded their own property. But unlike many politicians, Caesar did not crow at his opponents’ mistakes.

Caesar faced two main groups of opponents at the time he crossed the Rubicon: conservatives in the Senate and Pompey and his supporters. The senators stood on principle: they could not abide the thought of one man dominating Roman politics as a dictator, as the dictator Sulla had (82–79 B.C.). They saw Caesar as what might now be called a “red dictator,” someone whose populist policies might yield absolute power. Pompey didn’t care about principle; he cared about Pompey. Before Caesar had conquered Gaul, Pompey had been the dominant military-political figure in Rome. Now, his star was waning and Caesar’s was a supernova. Pompey would not share power with Caesar; the senators could not bear submitting to a fellow aristocrat turned populist demagogue. Not that they relished cooperation with Pompey, himself a dominant figure, but the senators correctly saw him as less of a threat to them than was Caesar. So they ordered Caesar’s arrest, and he responded by crossing the Rubicon with his army, aimed at Rome.

Many had doubted that Caesar would dare take this step, and for a good reason: he had only one legion in Italy, that is, five thousand men. Pompey had two legions (eight thousand to ten thousand men) and the authority to raise 130,000 new troops, to be led by himself and various prominent senators. Pompey also had seven legions in Spain and, although far off, they could be moved to Italy. Caesar had ten legions north of the Alps; as it turned out, three were ready to join him about a month later. Besides, he no doubt knew what a general would later say: “It is not the big armies that win battles; it is the good ones.”

If it seems surprising that neither side had a large army ready, remember, as Pompey and Caesar both did, that in a civil war, less is more. Both knew that the public wanted peace, so neither general wanted the blame for having provoked war. Each was willing to risk a lack of preparation in order to dodge responsibility for the war. The result was that once war broke out, the two sides each had to play catch-up. That favored Caesar.

Caesar had sole and supreme command of his forces, while Pompey had to share command with a committee of senators, each pulling in his own direction. Pompey and his allies in the Senate distrusted each other as much as Hitler and Stalin did after they agreed to carve up Poland together.

If Caesar coldly appraised Pompey before Caesar crossed the Rubicon, he would have had to admit that he faced a great general. Among Pompey’s achievements were victories in North Africa, Spain, the eastern Mediterranean from Anatolia to Judea, and on the high seas against the pirates. He was shrewd, disciplined, and a superb organizer. Yet, while Caesar had stormed through Gaul, Pompey had gotten used to a life of civilian ease: it had been nearly fifteen years since he had commanded in the field. On top of that, Pompey’s military specialty was defense. Caesar, on the other hand, specialized in what is today called shock and awe.

A good general needs to figure out how his enemy thinks. Before crossing the Rubicon, Caesar probably guessed Pompey’s strategy: rather than risk fighting Caesar’s hardened veterans of Gaul, Pompey would raise new troops quickly in Italy and then evacuate them to Greece. There he could train them into a great army, return with them to Italy, and defeat Caesar.

Caesar knew that Pompey held two aces. Unlike Caesar, Pompey had a navy, which meant that, after fleeing Italy, he could return in force by way of the sea. The East, furthermore, was his base, just as Gaul was Caesar’s base. Pompey had conquered much of the eastern Mediterranean for Rome in the 60s B.C., leaving him a gigantic network of men who owed him favors.

But Pompey needed time. He needed time to persuade the senators that it really made sense to evacuate Italy. Many of them would refuse to concede to Caesar the psychological advantage of controlling Italy’s “sacred soil”—a point made by none other than Napoleon, who studied ancient history while living out his exile. Pompey also needed time to recruit new troops in Italy. Unfortunately for Pompey, Caesar was the thief of time. The war was a race, and in military terms, Caesar was a champion runner.


By the time they invaded enemy territory, Alexander, Hannibal, and Caesar had each shown that he was dangerous. Each wielded the equivalent of a dagger: a loyal, veteran, and victorious army. Only two defenses were possible: to fight with equal force or to retreat. Retreat repels most soldiers but sometimes it is necessary for future victory, despite the accompanying shame. A retreat makes it possible to harass the enemy in skirmishes as they give chase, to deny him food by purposely destroying one’s own resources (a “scorched-earth” policy), and to regroup to fight again another day.

But still, retreat denies the men a fight, and few soldiers will tolerate that. Most armies choose to stand and fight, as the Persians did against Alexander and the Romans did against Hannibal.

Alexander: A Quick Early Victory

Things could hardly have gone better for Alexander as his army invaded Anatolia in spring 334. Getting from Europe to Asia required ferrying across the narrow waterway of the Hellespont (or Dardanelles as we know it). A strategic bottleneck, the Hellespont attracted antiquity’s naval battles the way a canvas ring attracts boxers, but Persia’s mighty fleet was nowhere to be seen. The Macedonians controlled both shores at the crossing point, and ancient navies did not like to fight without a friendly shore to retreat to. Alexander’s forces crossed unmolested and landed near Troy. They totaled about 50,000 men.

Their logistical base, however, was made of sand. Alexander had only a month’s worth of supplies. Worse still, he had no money. Macedon had spent its last drachma in putting together the invasion force. To feed his men, Alexander would have to persuade or force the cities of Anatolia to open their gates—and their granaries.

Darius did not take the Macedonian threat lightly. He saw to it that the five satraps of Anatolia’s great provinces met and pooled their military resources under the guidance of the leading mercenary general of the day. But that general did not have absolute command. In retrospect, Darius made a mistake by allowing a divided command when he should have enforced a single, united policy. Committees do not make good generals.

As Alexander’s army arrived on Asian soil, a council of Persian commanders met about seventy-five miles to the east, in the small city of Zeleia. Those present included satraps and members of the royal family as well as the greatest mercenary commander of the age, Memnon of Rhodes, a man “famous for his good judgment as a general.”

Memnon was Greek. It might seem surprising to find a Greek among Persia’s commanders, but it was a common sight. Persians made great cavalrymen but only mediocre infantrymen, while Greeks made excellent infantrymen. When it came to war, the Persian government was pragmatic and relatively open-minded, so it hired Greek soldiers and Greek generals.

Memnon came from the premier mercenary family of the age. He and his brother Mentor had spent twenty years in Persian service, where they rose to top positions. Yet they had married into Persia’s first family of rebellion, the family of Artabazus, satrap of Phrygia (an important area in northwestern Turkey). Mentor married Artabazus’s daughter Barsine; when Mentor died in 340, Barsine married Memnon. (Artabazus, by the way, married Mentor and Memnon’s sister.) In the 350s, Artabazus rebelled against the then Persian king Artaxerxes III. The tide of war ebbed and flowed until 352, when Artabazus and Memnon fled to Macedon and the court of Philip II. Mentor went to Egypt and eventually ended up back in the good graces of Artaxerxes III by helping to put down a rebellion there. In exchange, Artabazus and Memnon were pardoned and allowed to return to Persian territory in 343. They brought firsthand knowledge of Macedonian plans and power. When Darius III became king in 336, Memnon and Artabazus both served him loyally.

Memnon leveraged his knowledge of Macedon into a series of victories against Alexander’s advance forces in Anatolia from 336 to 335. In one battle, he even defeated the Macedonian commanding general, the great veteran Parmenio, and drove him back toward the Hellespont. But Memnon was shrewd, and he did not overestimate his success. He knew that it was one thing to defeat a small advance force and quite another to take on the main army led by its king.

Memnon knew just how seasoned and ruthless young Alexander was. Memnon concluded that a conventional battle against Macedon was too dangerous, because of the Persians’ inferiority in infantry. Instead, he “advocated a policy of . . . ravaging the land and through the shortage of supplies keeping the Macedonians from advancing further.” At the same time, he was pressing for a naval offensive.

Led by the local satrap, the men gathered at Zeleia rejected Memnon’s advice. They considered it their duty to defend their land, not to destroy it. They might also have disliked taking advice from a foreigner like Memnon. Some might even have questioned his loyalty, considering that the Macedonians had spared his estates near Troy from ravaging. (This was a bit of psychological warfare aimed at making the Persians distrust Memnon.)

The Persians at Zeleia decided to fight a pitched battle. They knew that Alexander outnumbered them in infantry but they probably also knew that most of Alexander’s 30,000 infantrymen were untested and untrustworthy allied troops. Persia had 6,000 veteran and reliable Greek mercenaries. Persia had the numerical edge in cavalry, 20,000 to 5,000. The Persians planned to make the Macedonians fight a cavalry battle. And they knew that they could fight on ground of their own choosing, because Alexander had to come to them.

As long as the Persians had an army near Zeleia, Alexander could not march south, because the enemy might then cut his communications with the Hellespont. So Alexander marched toward Zeleia, about three days away from Troy. As the enemy might have guessed, he left most of his 30,000 infantrymen behind; he took only 12,000 heavy infantrymen, all trusted Macedonians, as well as 1,000 light-armed troops from Thrace. He also brought his entire cavalry, 5,000 men.

The Persian army made its stand on the main east-west road, west of Zeleia. As Alexander’s army marched eastward, his scouts reported the location of the Persians at the far end of the Plain of Adrasteia, on the east bank of the Granicus River. The defenders had chosen good ground. Although the river was not deep (only about three feet in May), it was fast-flowing, slippery, and protected by steep and muddy banks. The Macedonians would have no easy time getting their men across and in good order. The Persians planned to take advantage of disarray in the enemy ranks to execute a strategy of decapitation. They would target Alexander and kill him.

It was already afternoon when the Macedonians located the Persians. Alexander’s advisors recommended delaying until the next day, in the hope that the enemy would withdraw from the damp river edge overnight, which would allow the Macedonians to cross in the morning. Alexander insisted on immediate battle. Usually a good psychologist, he knew that action would inspire his men and frighten the enemy.

The Persian cavalry lined the east bank of the Granicus, covering both the lip of the bank and a flat area going back about three hundred yards. They held their infantry, all Greek mercenaries, in reserve on the high ground behind them, knowing it would be pointless to deploy them against an enemy who outnumbered them. The infantry could be called in later, if needed.

On the other side of the river, Alexander’s Macedonians did not follow suit, but arranged their infantry between their cavalry on either wing. Alexander and the Macedonian cavalry held the Macedonian right wing; Parmenio and the allied, Thessalian cavalry occupied the left wing. As usual, the cavalry would strike first. They could not make a frontal assault, but their scouts had found a few gentle, gravel slopes along the steep banks of the river. The cavalry aimed for them as crossing places.

And so, the two waves of riders, with which this book started, attacked the Persians. Alexander began with a cunning move. He sent in a squadron of about one thousand cavalrymen, to draw the enemy off the bank and into the river. It succeeded, at a cost of heavy Macedonian casualties. Having forced the enemy to break up its line, Alexander now attacked. He led his men in oblique order heading upstream, that is, going farther to his right, in order to do two things. Alexander wanted both to outflank the Persians and to ensure that his men would present a solid front to the enemy rather than emerge from the river in column, where they could be picked off one by one. No novice, he had proven himself four years earlier by leading a cavalry charge against the Greeks at the Battle of Chaeronea.

The Persians were no tactical novices either. A wedge-shaped unit of horsemen, led by some of Persia’s leading men, bore down on the enemy. They aimed for Alexander, hoping to cut out the heart of the invasion by killing its leader. They almost succeeded. In fact, they would have changed history, had not Cleitus saved his king from Rhoesaces’s nearly fatal attack, as we saw in chapter 1.

Once the Macedonians rescued Alexander, their assault proved devastating to the Persians. For all the elegance of Alexander’s opening moves, Granicus came down to a brawl. The sources talk of shoving and of “horses fighting entangled with horses and men entangled with men.” Alexander’s men had better equipment and technical expertise, and many of them, especially his bodyguard, were simply big and strong. The Macedonians had cornel wood lances, heavy thrusting weapons that greatly outperformed the Persians’ light javelins, which were throwing weapons. A twelve-foot lance, with the weight of a galloping horse and rider behind it, could crush a skull, and the Macedonians aimed at the faces of the Persians and their horses. While Macedonian horsemen pushed the Persians back, Thracian light troops, who intermingled with the cavalry, added to the Persians’ woes. They were specialists at darting in and out of horsemen and hurling their javelins.

Meanwhile, in the center of the line, the Macedonian infantry advanced. With terrifying efficiency, and with their huge pikes held out before them, the men of the phalanx crossed the river, climbed the opposite bank, and forced the enemy back. The Persian center broke and the cavalry turned and fled. On the Macedonian left, the Thessalian cavalry fought with distinction. Persia’s Greek mercenaries stood in the rear, amazed and horrified at what was happening; apparently no one ordered them into action.

Alexander and his men won a great victory. It was a tribute to the army’s professionalism and its power and it reflected well on Alexander’s boldness as a field commander and courage as a warrior. But it also left an opening to the Persians, who had, after all, nearly killed their enemy’s king. Yet the Persians had access to huge manpower resources. If they mustered a big enough army, with plenty of Greek mercenaries and enough cavalry to surround the Macedonians on the wings, they stood a chance in battle.

Except for the squadron of one thousand cavalrymen, Macedonian casualties were light, although probably not as light as the pro-Macedonian sources claim: supposedly, just eighty-five cavalry and thirty infantry died. Macedonian casualty figures would increase in the battles ahead, but all in all, they stayed fairly low. That was one key to Alexander’s success: he spared his men.

He also lavished kindness on them. After the battle, Alexander made sure his wounded were treated well and went to the trouble of visiting them himself. He had the Macedonian dead buried with their weapons; he exempted their surviving families from taxes. Finally, he commissioned a bronze statue group in honor of the twenty-five Macedonian Companion Cavalry who fell in the first attack. Alexander gave the job to Lysippus, the most famous sculptor of the day, and had the statues erected in Macedonia.

Persian casualties were high. About a thousand Persian cavalrymen were killed. Eight Persian generals fell in the battle, including two satraps, the commander of the mercenaries, and two royal in-laws and a former king’s grandson. Another satrap escaped and committed suicide soon afterward. Memnon escaped as well, but he planned to keep up the fight.

The six thousand Greek mercenaries fared much worse. Because the fighting was all but over, the Greeks expected to be able to surrender. Instead, the Macedonians surrounded them and attacked. The Greeks defended themselves, and the Macedonians took casualties, but in the end it was a massacre. Only two thousand Greeks survived. They were sent to Macedon to do hard labor. Even by ancient standards, this was brutal, but the point was not military but political. Alexander wanted to brand any Greek who opposed him as a traitor. The message was aimed not only at Greeks in Persian service but also at potential rebels on the Greek home front.

To underline the message, Alexander sent three hundred captured Persian suits of armor to the Parthenon in Athens, with the inscription: “Alexander son of Philip and the Greeks except the Spartans, from the barbarians living in Asia.” In Greek terms, the inscription meant that Alexander was fighting for all Greece in a clash of civilizations against a savage enemy living on another continent. For all Greeks, that is, except the Spartans! This was an insult: in the old days, Sparta had stood against Persia at Thermopylae. Now, Macedon claimed to be the new Sparta. That would make Alexander a great hero, like Sparta’s legendary King Leonidas—except, of course, that unlike Leonidas, who died at Thermopylae, Alexander planned to live.

Hannibal: A Two-fisted Victory and Thirty-seven Elephants

The most impressive thing about Hannibal and his army as they exited from the Alps about November 218 B.C. was that they were there at all. They had just completed one of the great epic marches in the history of warfare. It was approximately a five-month, thousand-mile struggle against both natural and human enemies. Besides traversing the Pyrenees and the Rhône, they had to cross the Alps in the snows of late autumn. They fought hostile tribesmen and evaded a Roman expeditionary force. They suffered desertion, disease, battle casualties, and starvation. And then there were the elephants, those stunning beasts that Hannibal’s men ferried over the Rhône and drove through icy Alpine passes.

When the Carthaginian high command was debating the proposed march from Spain to Italy, one of Hannibal’s generals warned him of the dangers. The general, who was also named Hannibal but with the fierce nickname of “the Gladiator,” painted a picture of terrible logistical obstacles. The men would have to eat human flesh in order to survive, said Hannibal the Gladiator. That was an exaggeration, but not much.

Success had not come cheap. When Hannibal left Spain’s New Carthage in or around June, he had 90,000 infantrymen, 12,000 cavalrymen, and 37 elephants. He gave 15,000 troops to his brother Hasdrubal to hold central and southern Spain, while he gave 11,000 troops to pacify northeastern Spain; another 10,000 troops were sent home. Hannibal crossed the Pyrenees into France with 50,000 infantry, 9,000 cavalry, and the elephants. When he reached the Rhône about October, he had 38,000 infantry, 8,000 cavalry, and thirty-seven elephants; most of the recent losses were due to desertion. Then, he crossed the Alps in about fifteen days. By the end of November, about five months after starting his journey, he reached Italy with only 20,000 infantry and 6,000 cavalry—the Alpine trek had cost him nearly half his remaining soldiers. Some died in combat with the hostile mountain peoples, while others succumbed to the snow and cold. Many others simply deserted. No doubt Hannibal had expected some losses on the march, but probably not on this scale.

Polybius emphasizes how much the elephants helped Hannibal’s army in the Alps. Neither he nor any other source mentions the loss of any elephants there, although they do state heavy losses among horses and pack animals. Perhaps all of Hannibal’s original thirty-seven elephants survived the Alps.

Desertion was the prime cause of Hannibal’s losses in manpower. The good news, however, was that most of his best troops were still with him. They came from North Africa, and that was too far to run home to. Most of the deserters were probably Spaniards. Yet, they were good soldiers too.

Hannibal’s ability to hold the best part of his army together under awful conditions is a tribute to his leadership. Still, there is no way to get around it. Hannibal left Spain with 59,000 men and reached Italy with 26,000 men. In the campaign season that followed, his main problem was a lack of manpower. So, Hannibal’s initial losses haunted him for years to come.

Hannibal’s remaining army was in bad shape by the time it reached Italy. “For his men had not only suffered terribly from the toil of ascent and descent of the passes and the roughness of the road,” writes one ancient writer, “but they were also in wretched condition owing to the scarcity of provisions and neglect of their persons, many having fallen into a state of utter despondency from prolonged toil and want of food.”

Given the size and shape of the army that staggered into Italy in November 218, the war might have been over. Hannibal could not defeat Rome in the long run without substantial reinforcements. But in the short run, Hannibal turned things around, which is a tribute to his leadership and to his men’s toughness. Not only that—he went on to win battlefield victory after victory, which seems almost miraculous.

Like Alexander, Hannibal drove his men hard but he knew their limits. They needed rest, which Hannibal gave them. The men also needed food, but the only way to get food was to fight the enemy and take his resources—hard work, but victory would restore both the Carthaginians’ bodies and their morale.

Within a month or so of arriving in Italy, Hannibal achieved that victory, indeed several victories. He gave a virtuoso display of his skill as a commander. As a diplomat, he alternated between policies of terror and appeasement and won gains with both. As a manager, Hannibal proved that he knew men as well as he knew war. As a commander, he applied a combination of cunning, ingenuity, and fortitude that defeated Roman armies twice, first in a cavalry skirmish and then in a pitched battle. And he accomplished it all by the winter solstice, about December 22 or 23, 218 B.C.

But the Romans racked up a string of accomplishments as well. They demonstrated that they could think strategically. Although they could not match Hannibal’s tactical skill, they showed guts and endurance. The Roman infantry—the famed legions—could throw a powerful punch, and Hannibal now knew it from personal experience. Like the Carthaginians, the Romans exhibited mobility and speed in their operations. Indeed, a neutral observer at the end of the year 218 would have gasped at the distances that the two sides had each covered, at the rapidity with which they had moved, and at the flexibility with which they shuffled pieces on the military chessboard.

When it came to strategic surprise, however, Hannibal had the edge. The Romans expected him to stand on the defensive, so they were stunned by his aggressive march to Italy.

After leaving the Alps, Hannibal headed for the Po River Valley, where his agents had already made contact the previous spring with the largest Celtic tribes—Rome’s longtime enemies. The mighty Po flows from the Alps to the Adriatic. Whoever controlled its valley controlled northern Italy. The Romans had fought the Celts for control of this area and only recently emerged on top. First Hannibal had to pass through the area around modern Turin, whose Celtic inhabitants were not friendly to him. He attacked their main town and slaughtered the residents. The other tribes around Turin learned their lesson and joined him.

The Romans, meanwhile, hurried to the scene. After declaring war on Carthage the previous summer, they had decided on a two-pronged offensive, with attacks in both Spain and North Africa. When news of Hannibal’s approach in southern France came, they cancelled the African offensive but decided to keep up the pressure on Spain, Hannibal’s base. Rome wisely recognized that the struggle might be long, and so it was crucial to prevent Hannibal’s Spanish reinforcements from joining him.

Before Hannibal’s arrival in Italy, Rome had sent troops to the Po River Valley to deal with Celtic unrest. Just a few months before, it had also founded two new military colonies in the valley, one at Cremona and the other at Placentia (Piacenza), each in a strategic location. As Hannibal approached, even more Roman troops marched to northern Italy under the command of Tiberius Sempronius Longus, one of the two consuls (chief officials, annually elected) for 218 B.C. The other consul, Publius Cornelius Scipio, was in charge of the Spanish expedition, but he turned command in Spain over to his lieutenant (and brother) and made haste to northern Italy as well.

The campaign of November to December 218 focused on the strategic triangle represented by three points, the cities of Placentia, Clastidium, and Ticinum. Placentia, the new Roman colony on the central Po, stood just east of the valley of the Trebbia River and the pass that led to the northern Italian port city of Pisa. Farther west of Placentia, a spur of the Appenines reached up from the south and nearly touched the Po, making this a strategic chokepoint. Just west of that lay Clastidium (modern Casteggio), a Celtic fort that the Romans had taken over and turned into one of their strongholds. Both Placentia and Clastidium lay on the south side of the Po. On the north side, just east of Clastidium, the Ticinus River flowed into it. A few miles upstream on the Ticinus lay Ticinum (modern Pavia), a Celtic settlement. Whoever held these three cities had the key to the Po River Valley.

Scipio, the first Roman on the scene, was also the first Roman to taste battle with Hannibal. Using Placentia as a base, he went on the offensive. Scipio’s engineers threw makeshift bridges over the Po and the Ticinus and he ordered his troops to cross the rivers in search of Hannibal. On the plain somewhere to the west of the Ticinus and north of the Po, Scipio found him. The date was about late November 218.

The flat plain was classic cavalry country, or it would have been had it not been pockmarked by woods, swamps, and streams. Those features rendered it perfect for the kind of ambushes and suprises that Hannibal loved to carry out. He was a tactical master, not least in exploiting geographical features to the maximum. Hannibal most likely employed such tactics in this terrain.

The Ticinus River was more a cavalry skirmish than a proper battle. Cavalry was never Rome’s strongpoint; the Roman army was primarily an army of foot soldiers. Hannibal’s cavalry both outnumbered and outclassed the Romans. His heavy cavalry consisted of Spaniards, and Hannibal attacked the Romans with them in the center. Meanwhile, he made good use of his light cavalry, the dazzling horsemen from Numidia (modern Algeria). Specialists at harassing and breaking up enemy formations, the Numidian horsemen at the Ticinus River rode around the Roman flank and charged their rear. Not only did the Romans turn and flee, but they almost lost their commander, Scipio. His wounded body was dragged to safety and, according to one tradition, he was saved by his nineteen-year-old son, also named Cornelius Scipio (later Scipio Africanus), the very man who would eventually defeat Hannibal, sixteen years later.

Scipio had badly underestimated Hannibal. Perhaps that is understandable, given both Hannibal’s youth and the information that Scipio probably received about the poor state of Hannibal’s army after it had straggled out of the Alps. Or maybe Scipio had a chip on his shoulder. When the Carthaginians had crossed the Rhône in southern France in October, Scipio had tried—and failed—to reach them in time to stop them. Humiliated, he then returned to Italy.

After their defeat across the Ticinus, the Romans retreated rapidly, leaving forces beyond to break up the bridges after them. They regrouped to the southeast near the Roman colony at Placentia on the Po. Hannibal followed, picking up Celtic allies and Roman prisoners along the way. He gained entry to Clastidium, when its commander opened the gates: he and the men in his garrison were Roman allies from southern Italy. The Carthaginian turned the occasion into a propaganda event, treating the prisoners ostentatiously well and even honoring their leader. By trying to woo Rome’s allies, Hannibal made war on the political as well as the military front. Meanwhile, a group of Rome’s Celtic allies left Scipio’s camp to join Hannibal and made a different kind of statement. They killed some of the Romans and cut off their heads to bring with them.

•  •  •

The two sides encamped in the valley of the Trebia (Trebbia) River, west of Placentia and south of its confluence with the Po. In early December, Tiberius Sempronius Longus and his troops joined Scipio and his men. Hannibal’s army had grown to 28,000 infantry but the Romans, with 36,000 to 38,000 infantry, outnumbered him. Yet Hannibal had 10,000 cavalry while Rome had only 4,000. Finally, there were still about thirty-seven elephants.

The two sides sparred and skirmished. One raid almost turned into an all-out battle, as Hannibal’s hard-pressed soldiers retreated in disorder. But Hannibal demonstrated his iron grip on his troops. He sent out officers and buglers with specific instructions. The men in retreat had to stand and hold their ground, but that was that; he would not let them go on the offensive. Hannibal refused to be drawn into a battle except on his terms, that is, in a place, at a time, and under circumstances that he had carefully chosen beforehand. He was, as we might say today, a control freak.

But Hannibal did have a general engagement in mind at the Trebia, and on carefully selected ground. He chose the wide fields west of the river, where the flat and treeless plain was crisscrossed with gullies.

Hannibal knew that the Romans practically smelled ambushes when they entered the woods and would be on their guard. The open country, though, would invite Roman carelessness, Hannibal reasoned. One night, he managed to hide two thousand men in an overgrown gully behind the likely Roman battle line.

Hannibal knew his enemy. As Polybius wrote, Hannibal understood that nothing is “more essential to a general than the knowledge of his opponent’s principles and character.” A general has to envision the weak spots not only in his enemy’s body but in his mind. Hannibal did just that and Polybius was all admiration.

The next morning, Hannibal lured the Romans out to battle, under Sempronius’s command. The Numidian cavalry taunted the Romans and they took the bait. Having seen the Carthaginians retreat, Sempronius might have mistakenly thought that he had them on the run.

Before going out to fight, Hannibal prepared his troops carefully. He fed them a good breakfast, warmed them around the campfires, and told them to rub themselves down with olive oil as protection against the cold. The Romans, however, had no time for breakfast and did not protect themselves with oil. The Carthaginians had only a short distance to go to reach the battlefield. The Romans had to travel farther, and they had to cross the river. The water was cold and breast high, leaving them drenched and tired by the time they reached the enemy. It was the winter solstice, around December 22 or 23, 218 B.C.

As at the Ticinus, Hannibal planned to win by enveloping his enemy’s flanks. He arranged his infantry in the center and divided the cavalry between the two wings. Hannibal divided the elephants too and placed them in front of the infantry on either wing. Roman armies deployed their legions in three lines, with the cavalry on the flanks, and Tiberius Sempronius Longus did so as well. In the battle that followed, Rome’s always powerful legionaries held their own against the Carthaginian center. But the Carthaginians overwhelmed the enemy’s wings. After driving the Roman cavalry from the field, Hannibal’s men used a combination of cavalry, skirmishers, and elephants to break the Roman flanks. Meanwhile, the two thousand Carthaginians hidden in the gulley rose up and attacked the Romans in the rear.

The Roman legionaries in the center—ten thousand men—managed to escape by punching through the enemy line. Most of the cavalry escaped as well. But two-thirds of the Roman army—about twenty-eight thousand men—was killed or captured. Hannibal’s losses consisted mainly of Celtic infantrymen in his center. Wintry weather after the battle killed most of Hannibal’s surviving elephants.

Tiberius Sempronius Longus did not dare send the truth about the battle to Rome; instead, he sent a message that a storm had deprived him of victory. Hannibal was a tempest, all right, but one whose cunning and agility left Rome in shock.

As the truth about the Trebia percolated to Rome, Hannibal struck another propaganda blow. While barely keeping his Roman prisoners alive, he treated the Italians respectfully. He called an assembly in which he said that, “he had come above all to give the Italians back their freedom and to help them recover the cities and the territories which the Romans had taken away.” Then he sent them home without asking for any ransom.

Hannibal delivered a dual message: slaughter and liberation. The question was whether it would drive a wedge between Rome and its allies.

Caesar: The Audacity of Terror and the Sting of Clemency

Caesar made his first move with a wolf’s speed and agility. Before crossing the Rubicon he sent centurions in civilian clothes into Rimini, a key city at the junction of two Roman roads. On January 12, 49 B.C. (November 24, 50 B.C. by the solar calendar), Caesar crossed the Rubicon. By the time he marched on the city with his legion, Caesar’s men had opened the gates. Rimini surrendered. It was a sign of things to come.

As one ancient writer says of Caesar, “He thought surprise, daring, and taking quick advantage of the moment could achieve more than preparing for a regular invasion; he wanted to panic his enemies.” Another says that because Caesar “used to depend on the surprise caused by his speed and the terror caused by his audacity, rather than on the immensity of his preparations, he decided, with his 5,000 men, to be the first to attack in this great war and to seize the strategic positions in Italy before the enemy.” Such methods worked.

Within a month, Caesar and his men took the major towns in northern and central Italy. They did not need to shed any blood. In some places the enemy fled, in other places, they surrendered, either on their own initiative or because of local pressure. Italians reacted with horror to find in their backyard the army that had conquered Gaul.

Meanwhile, Pompey left Rome, first to Capua and then to Luceria, a city on the Apulian plain. It takes a shrewd and seasoned commander to engage in a fighting retreat; Pompey was such a general. Critics accused him of cowardice, but Pompey and his lieutenants were raising troops in central and southern Italy and then moving them south. They kept just one step ahead of Caesar’s advance. Things went rather smoothly until Corfinium.

Corfinium sums up the politics of the civil war in Italy. It was the only place that offered any real resistance to Caesar. But Corfinium wasn’t just a military operation; it was a “new type of conquest,” as Caesar himself said. Corfinium symbolizes the brilliance of his policy—and its risks.

Geography made Corfinium. It sat high in the Apennines, in a fertile valley hemmed in by mountains. The town lay about 100 miles due east of Rome on the ancient via Valeria, the highway to the Adriatic Sea. Other strongholds nearby controlled roads to the south and west.

About forty years earlier, in 90 B.C., the Italian rebels against Rome had chosen Corfinium as their capital in the Social War (91–88 B.C.). They renamed it Italica and gave it a new forum and Senate house, but they soon surrendered the town to Rome. Apparently, there was no struggle—otherwise Rome would have destroyed the city’s fortification walls, which still stood in 49 B.C. Elsewhere in Italy, the Social War was hard fought. Rome put down the rebellion but agreed to the allies’ demand for Roman citizenship.

The city’s strategic position remained obvious. As he marched south, Caesar could not afford to bypass Corfinium and leave a strong enemy force in his rear. If the enemy chose to make a stand there, he would have to fight. And so it happened.

In February 49 (by the Roman calendar: December 50 by the solar calendar), as Caesar approached from the north, Lucius Domitius Ahenobarbus decided to dig in at Corfinium. Domitius was a man of grand gestures and extreme opinions, famous for bringing one hundred African lions to the arena and for marrying the sister of Cato, the archconservative of the Roman senate. How appropriate that the emperor Nero was Domitius’s great-great-great-grandson!

When it came to Caesar, Domitius was a fire-eater. He came from a rich family whose prominence extended to the dawn of the Roman republic. Domitius had often publicly attacked Caesar and, for that matter, Pompey too, before Pompey split with Caesar. Domitius had once threatened to recall Caesar from Gaul; the Senate had recently appointed him to replace Caesar as governor there. An ex-consul, Domitius was now a leading general of the Senate’s armies.

In the second week of February, he decided to stand his ground at Corfinium. Pompey had already evacuated his forces to Luceria, about one hundred miles southeast of Corfinium. Domitius might have joined Pompey there, but he reasoned that it was better to make a stand in a stronghold on the road to Rome than in open country far from the capital. He had no small force of men in and around Corfinium, having raised twelve cohorts of troops from the tough mountain peoples in the vicinity. Pompey’s lieutenants brought another nineteen cohorts from central Italy, for a total of thirty-one cohorts: on paper, about fifteen thousand men. But fearing that Caesar would cut Domitius off, Pompey sent an urgent message to withdraw.

By now, Caesar had two legions, or eight thousand to ten thousand men. He arrived at Corfinium on February 15 and set up camp outside the city walls. Seven of Domitius’s cohorts in a neighboring town immediately defected to Caesar. Two days later, another legion, twenty-two newly recruited cohorts from Gaul and three hundred foreign cavalry joined Caesar, for a total of about 27,000 to 30,000 men. Caesar outnumbered Domitius by about two to one.

When Caesar reached Corfinium, Domitius had sent messengers to Pompey, asking him to come quickly with his forces to block the passes, cut off Caesar’s supplies, and trap him between their two armies. While he was waiting for help to arrive, Domitius organized his troops in defensive positions, arranged artillery on the city walls, and called an assembly in which he pledged a piece of his own land as a reward to each soldier.

It was no use, however. Winters in Corfinium are mild enough for military operations, and Caesar moved with vigor. He added a second camp on the far side of town; he fortified both camps with great earthworks. Then he prepared to lay siege to Corfinium by building walls and forts to surround it. For good reason Caesar was known as a great engineer! Pompey, meanwhile, wrote back to Domitius. His reply arrived on February 19 and stated a clear no. Far from bringing his forces to Corfinium, Pompey again advised Domitius to get his army out and join him in Luceria; doing anything else was too risky. Pompey would have ordered Domitius to join him if he could, but he wasn’t able to. Unlike Caesar, Pompey lacked supreme command.

What Pompey did insist on, though, was that he had neither advised nor wanted Domitius to make a stand at Corfinium. Far from fighting in Italy, Pompey decided to evacuate the peninsula. He would move east, and with the help of his vast contacts in the Greek world build a new army. If Domitius knew that, he didn’t agree. If Pompey left Italy and stormed back to victory with help from his friends in the East, he would owe the Senate nothing. But if they beat Caesar at Corfinium now, the Senate would share the credit. Pompey was unmoved, stating that he could not possibly stand up to Caesar’s veterans.

So Domitius was left on his own. He tried to rally his men but they knew a hopeless situation when they saw one. They were trapped in the mountains and under siege by the best army in the Roman world. Claiming that their general was trying to escape, his own officers arrested Domitius. Whatever the real story, Domitius made a good gift for Caesar, to whom they promptly offered to surrender. It was February 21. Pompey had already left Luceria and moved farther south, to the heel of the Italian boot.

In only seven days, the great fortress of Corfinium had fallen. That, however, is not the most striking part of the story; that distinction belongs to what happened next, when it was time for Caesar to take vengeance: nothing. Caesar prevented his soldiers from entering the city and looting it. Meanwhile, he received the elite among the town’s defenders: fifty men, including senators, public officials, and their sons. Caesar pardoned all of them. Domitius asked for death; Caesar not only gave him life but returned the six million sesterces (Roman coins) that Domitius had brought to town (and which the town authorities had turned over to Caesar). “This he did,” wrote Caesar, “in order not to seem more self-controlled in regard to men’s lives than their money.”

It was a remarkable display of generosity, and Caesar knew it. In a letter that he wrote to Cicero the following month, Caesar pointed out his determination not to follow the bloody road of Sulla the dictator, who had killed thousands in Italy. “Let this be the new type of conquest,” Caesar wrote, “to fortify ourselves with pity and generosity.”

Caesar’s policy was generous but also political: he wanted to win the goodwill of all Italians. He also wanted to win the support of Domitius’s soldiers, whom he immediately ordered to join him by taking a loyalty oath. Caesar had not only added fifteen thousand soldiers to his army, but he had deprived Pompey of them. Because it was a civil war it was not unusual for men to switch sides.

By his policy of clemency, Caesar branded himself as a conqueror who displayed generosity—but with a bite. In Roman eyes, clemency was a gift to a defeated, foreign opponent. There was, then, an insult in Caesar’s gesture, and everyone knew it. Cicero, for example, called it “insidious clemency.” Caesar’s opponents would never forgive him his mercy. No wonder that many of the men who stabbed him to death on the Ides of March, five years later, had been pardoned by Caesar.


Starting a war is not like taking out a certificate of deposit. There is no guaranteed rate of return. Think of war, rather, as a high-tech start-up. If a commander has done his job properly, the enterprise will rest on a firm foundation, but it is a risk, even so. There are no sure things in war. From Caesar at the Rubicon to the present day, war remains a high-stakes gamble.

Yet the paradox is that our three generals each would have found peace too risky. Peace would have cost Caesar his career and possibly his life. The Macedonians would never have tolerated Alexander if he had refused to invade Persia. Hannibal’s fear of Rome might have contained an element of paranoia, but it was shared by most of Carthage’s power brokers. Daredevil though they sometimes were, Alexander, Hannibal, and Caesar each played it safe by going to war. Peace was a sure thing—and it spelled ruin. War was risky but when risk is the only way out, it is the smart move.

Not that their wars were easy; far from it. But Alexander, Hannibal, and Caesar each made it look easy, and therein lies part of their greatness. Alexander had an empty treasury, a restive rear, and a record mostly of failure by his advance troops in Anatolia up to that point. Caesar had only one legion to pit against the Roman state. Hannibal had even bigger problems, above all, the daunting journey from Spain to northern Italy. By the time he crossed the Alps, about five months after starting out, he had lost nearly half his forces. Yet more important, he had made the trip—and then went on to win a battle.

Like any good general, Hannibal had prepared as carefully as possible. “Men are apt to think in great crises that when all has been done they still have something left to do and when all has been said that they have not yet said enough,” wrote Thucydides around 400 B.C., and the words continue to ring true. Yet they don’t tell the whole story.

Success in war depends not only on knowing yourself but your enemy. Within a month of stepping onto enemy soil, Alexander, Hannibal, and Caesar had the right to feel that they had judged their enemy correctly. Alexander had counted on the Persians challenging him to a pitched battle rather than adopting a scorched-earth policy. Hannibal had made a similar assessment about the Romans. Events proved each of them correct. The battles of the Granicus River, the Ticinus River, and the Trebia respectively were triumphs for the two invading war machines.

Caesar might have hoped that Pompey would do him the favor of engaging Caesar’s veteran army in a pitched battle, but that wasn’t likely, as Caesar surely had known. Pompey’s more probable policy would not have been a mystery to a man of Caesar’s wiles: recruiting soldiers and rapidly withdrawing them eastward. The best that Caesar could have hoped for was to chase Pompey out of Italy before he could raise many troops. Domitius’s clumsy stand at Corfinium was a lucky break for Caesar. But six weeks after crossing the Rubicon, Caesar had still not caught Pompey nor stopped him from leaving Italy with his army.

Of the three generals, Alexander had the best war so far. He had brought his army across the Hellespont without opposition, won a pitched battle at the cost of few casualties, and stood poised to take control of Anatolia’s western provinces and their resources. Caesar captured an enemy army led by a clumsy foe and he scored propaganda points through generous behavior, but he had yet to catch his main opponent, Pompey, and his army. Hannibal had the most difficult war because of his punishing losses on the march to Italy. In the long run, he needed reinforcements. Still, Hannibal had held his men together, reached Italy and hooked up with his allies, and he had smashed the Roman army, all considerable successes.

Alexander, Hannibal, and Caesar had each begun his war well. But none of them had the luxury of mistaking beginner’s luck for final victory. Their wars, like any new enterprise, would be judged by their ultimate achievements, not their initial performances—even though those performances had been spectacular.

Wars, in fact, have a way of getting more complicated the longer they go on. Once hostilities begin they take on a logic of their own. Having survived the initial shock, each side tends to increase its investment, which decreases its willingness to give in. The result: what might have seemed like a decisive move before the war turns out to be just an opening gambit once the fighting is under way.

In the opening stages of war, Persia, Rome, and the coalition of Pompey and the Senate had all been hit hard. But none of them was ready to quit.

For Alexander, Hannibal, and Caesar, therefore, the wars had just begun.

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