Military history


The collapse of Alexandrian Hellenism in the East was matched at home also, though not through the quarrels of his successors. The power of the house of Macedon in its heartland, and over Greece also, was eventually overthrown by a people insignificant in Alexander’s time, the Romans. Rome owed much to Greece for its rise. In the sixth century BC it was little more than a village on the banks of a river, where three tribes bearing Etruscan names, evidence of the dominance of Etruria to the north, lived under the rule of a king. During the reign of Servius Tullius, 580–30 BC, the population was supposedly organised into five military classes drawn from the propertied, and a militia was founded which certainly practised hoplite tactics.44 The Romans later claimed that they took their tactics from the Etruscans, but it seems more probable that they were imported from the Greeks, probably those living in sizeable numbers in southern Italy. At about the same time a republican form of government replaced the monarchy, and it was under the republic that Rome first began to extend its area of control, initially by conflict with the Etruscans, themselves under pressure from the Gauls of northern Italy, then with the Gauls directly, finally with the Samnites to the south. When Rome’s southern expansion brought her into contact with the Greek colonies in Calabria and Apulia, in the third century BC, they sent for help to Pyrrhus, ruler of one of the Alexandrian successor kingdoms in Greece; though victorious, he was so shaken by the costs of fighting a Roman army, particularly in the battles of Ausculum (299) and Beneventum (295), that he abandoned the campaign.

The Roman army had by now moved far in organisation from the hoplite model on which it was based. During their wars with the Gauls, who fought in a loose but dynamic open order, the Roman commanders had found that the tight ranks of the phalanx put their troops at a disadvantage. They had therefore introduced a system which allowed subsections, ‘maniples’ or handfuls, to manoeuvre on the battlefield and had progressively abandoned the thrusting spear in favour of a javelin, the pilum, which, when thrown, the soldier followed sword in hand. Increasingly, too, the soldiers of the legion, as the groups of maniples which constituted a division came to be called during the fourth century BC, dispensed with the heavy hoplite equipment; they adopted a light, oblong shield and, eventually, standard and much lighter body-armour of hooped iron, which would not have been proof against the pike-thrusts of phalanx fighting but served adequately to deflect sword-blows and missile-points. As important for the long-term efficiency of the Roman army as this change in equipment and tactics was the introduction of a new basis of service. Though by their frequent hiring of mercenaries the Greek city states had eventually compromised the principle that the citizen supported himself in the field, and while some were even driven to equip and pay their servicemen at public expense — by 440 Athens was paying its galley crews and overseas garrisons — the duty of the hoplite to campaign at his own expense remained an ideal.45 By the fourth century Rome had abandoned it, and was paying the legionaries a daily stipend. This development marked the most important divergence of the Roman from the Greek military system. Rome’s smallholders, at the dictate of an increasingly dominant political class, ceased to be attached to and supported by their land and became a recruiting pool for a professional army which campaigned, year after year, farther and farther from home, as the Roman republic extended to form an empire.46

Rome’s imperial motives are much disputed by scholars. It was the traditional view, certainly one supported by Roman sources, that an economic motive lacked. Rome certainly did not need to find food for a growing population, as Athens did, since rich lands were easily annexed within a short campaigning distance of the city. On the other hand, Rome grew rich by conquest, and its empire’s expansion fed on itself. Certainly, at the outset of the period of expansion, there was great enthusiasm for the acquisition of new land in Italy, both to provide estates for the political class and plots for the cultivators, and the state found no shortage of takers to buy or rent what it acquired by conquest; the agricultural colonies it founded were quickly settled and generally flourished. Yet arguments that Rome’s wars were deliberately undertaken to amass slave populations as a labour force on the expanding estates of the political class appear farfetched, as do those that Roman governments thought in such primitive terms as loot; the Italy which succumbed to Roman conquest was a largely moneyless region, and had little to yield in precious metals or minerals or rich artefacts. Nevertheless, ‘it was scarcely possible for a Roman to disassociate the expectation of gain from the expectation of successful war and conquest’. The two went together in the Roman outlook, as is best expressed by the classical historian William Harris: ‘Economic gain was to the Romans … an integral part of successful warfare and of the expansion of power.’47

What most distinguished the warfare of the Romans from that of their contemporaries and neighbours was not its motivation — in that respect it was the headstrong and individualistic Greeks who stood apart — but its ferocity.48 So ferocious were the Romans of the later first millennium BC that, in broad historical perspective, their behaviour bears comparison only with that of the Mongols or Timurids 1500 years later. Like the Mongols, they took resistance, particularly that of besieged cities, as a pretext justifying wholesale slaughter of the defeated. Polybius, the foremost Roman historian of the city’s early military history, describes how Scipio Africanus, after storming New Carthage (Spanish Cartagena) in 209 during the Second Punic War,

directed [his soldiers], according to the Roman custom, against the people in the city, telling them to kill everyone they met and to spare no one, and not to start looting until they received their order. The purpose of this custom is to strike terror. Accordingly one can see in cities captured by the Romans not only human beings who have been slaughtered, but even dogs sliced in two and the limbs of other animals cut off. On this occasion the amount of such slaughter was very great.49

The experience of New Carthage was widely repeated, sometimes in cities that had capitulated in the hope of averting a massacre, and even on the field of battle; Macedonians who fell in the campaign of 199 BC were later found by their companions as dismembered corpses, a sacrilege to all Greeks, who thought it a duty to bury the dead of battle, whether friend or enemy. The practice persisted into the first century AD, if the archaeological evidence for a massacre at Maiden Castle in Dorset, during the second Roman invasion of Britain, bears the interpretation usually put on it.

Harris concludes:

In many respects, [the Romans’] behaviour resembles that of many other non-primitive ancient peoples, yet few others are known to have displayed such an extreme degree of ferocity in war while reaching a high level of political culture. Roman imperialism was in large part the result of quite rational behaviour on the part of the Romans, but it also had dark and irrational roots. One of the most striking features of Roman warfare is its regularity — almost every year the Romans went out and did massive violence to someone — and this regularity gives the phenomenon a pathological character.50

In the context of comparative military history, this should not surprise us. The impulse to violence takes many forms, we have seen, and if most people shrank from expressing it directly when to do so entailed risk to their own bodies, a minority did not. Phalanx warfare, though it limited its effects by its essentially ponderous nature, inflicted appalling violence at the moment of contact, and to engage in it demanded a violation of both the instinct of self-preservation and the widespread cultural inhibition against face-to-face killing. What the Greeks learned to overcome in one fashion, the Romans learned in another. For all their social and political sophistication, they seem to have preserved from somewhere in their primitive past sufficient of the psychology of the hunter to fall on fellow humans as if on animal prey, and do their victims to death with as little regard for life as is sometimes shown by one wild species for another.

Yet Roman warfare, for all its episodic extremism, never achieved the levels of inhumanity and destructiveness reached later by that of the Mongols and Timurids. The Romans worked by piecemeal annexation and consolidation of territory — Caesar’s conquest of Gaul was an isolated exception — and after the Punic wars they did not set out to rampage, terrorise and destroy as Tamerlane was to do. They built no pyramids of skulls; and if they set up military colonies on the boundaries of their possessions, as in Liguria in the third century BC, Roman citizens willingly settled this land, not displaced subject populations shifted from their homelands as a punishment for untrustworthiness — the practice instituted by the Assyrians and carried on by Mongols, Turks and eventually Russians.

The comparative restraint of their imperial method has several explanations. The first was that the Roman army lacked mobility of the order displayed by the horse peoples. A Roman legion of the fourth century BC included a sizeable cavalry contingent, but thereafter it declined to an auxiliary fragment, for both social and material reasons: Italy, like Greece, will not bear a large horse population, while the original knightly class progressively abandoned campaigning in the field to pursue politics in the city.51 On the march, the legions displayed from the start of the era of expansion a remarkable ability to cover ground at a regular pace, day after day, and the state to provide it with pay and matériel. By its nature, however, an infantry army proceeds deliberately, not by dynamic surges, as conquering nomads do, so that Rome’s expansion was cumulative rather than cascading in character.

Moreover, the cumulative pattern of expansion was determined by the nature of the Roman army itself, which became ‘regular’ and bureaucratic at an early stage and, by the time of the Punic wars against Carthage, had achieved a form from which it was not to diverge until the onset of the empire’s troubles with the Teutonic barbarians in the third century AD. Historians credit Assyria with having inaugurated the regular system, and it indeed seems probable that the practices it instituted, including those of regular payment of full-time servicemen, establishment of arsenals and depots, building of barracks and centralised manufacture of equipment, did set a pattern for that of other, later empires; it percolated from the Middle East to zones of intense military activity farther west during the sixth and fifth centuries BC, partly through the Persians’ contact with the Greeks, partly through the rise of the market in mercenaries who had to be supported from state treasuries. No army before that of the Roman republic, however, achieved its level of legally and bureaucratically regulated recruitment, organisation, command and supply. From the Punic wars onward, it stood apart from all other institutions in the civilised world — perhaps its only, though invisible, equivalent was the Chinese mandarinate — as a phenomenon of confident self-sufficiency.

Its ability to persist successfully in unrelenting warmaking, whether in wars thrust upon Rome or deliberately undertaken, derived in large measure from the state’s solution of all centralised governments’ besetting military difficulty: that of assuring a steady source of reliable and effective recruits. By the time of the Punic wars, the militia obligation, though theoretically still in force, had lapsed and the legions were manned by a selection process, the dilectus, by which the best of willing citizens who presented themselves were enrolled for a six-year term of service (which might be extended to as many as eighteen years). The adoption of the dilectus reflected a worsening of the small farmers’ circumstances, and indeed the expanding estates of the rich were extinguishing the basis of smallholding; nevertheless, paid voluntary service seems to have been a popular enough alternative to farming for there to have been no need for laws reducing the term of service until the late second century BC.52 There was no need to apply the dilectusto those assigned high rank in the legions since the Roman political system, at least until then, made it a condition of candidature for elective political office, leading to that of the ruling consulate, that young men of good birth must have first completed a statutory period of duty as a tribune, of which there were six to each legion; ten years of service, or ten campaigns, seem to have been the qualifying norm. In the later empire, and particularly during the military crises of the third century AD, the imposition of the qualification would lapse, but neither republic nor empire ever shed the view that right to rule was ultimately legitimised by ability to command in the field.53

Yet the ultimate strength of the Roman army, and the characteristic that made it the model, a millennium later, for those raised in the dynastic states of Europe, following the revival of classical learning at the Renaissance, from which the great modern armies descend, was supplied neither by its system of recruitment nor by its high command but by its legionary encadrement, the centurionate. The Roman centurions, long-service unit-leaders drawn from the best of the enlisted ranks, formed the first body of professional fighting officers known to history. It was they who imbued the legions with backbone and transmitted from generation to generation the code of discipline and accumulated store of tactical expertise by which Roman arms were carried successfully against a hundred enemies over five centuries of almost continuous warmaking.

The Roman historian Livy has preserved for us the record of service of a republican centurion which exactly conveys the ethos of this remarkable body of men, and it emphasises how revolutionary was the institution of the centurionate in a world where hitherto military service had been largely an intermittent, emergency or mercenary business; indeed, it might, with appropriate substitutions, stand as that of a regular warrant officer in any great modern army. Spurius Ligustinus told the consulate of 171 BC:

I became a soldier in the consulship [of 200 BC]. In the army which was taken over to Macedonia, I served two years in the ranks against King Philip; in the third year because of my bravery [I was given] a post as centurion in the tenth maniple of the hastati [a term, with those of triarii and principes, surviving from the original ranking of legionary maniples by property qualification]. After Philip’s defeat, when we had been brought back to Italy and released, I immediately set out for Spain as a volunteer with the consul M. Porcius [195 BC]. This commander judged me worthy to be assigned as centurion of the first century of the hastati. For the third time I enlisted again as a volunteer in that army which was set against the Aetolians and King Antiochus [191 BC]. By Manicus Acilius I was made centurion of the first century of the principes. When Antiochus had been driven out and the Aetolians subdued, we were brought back to Italy. And twice after that I served in campaigns where the legions were in commission for a year. Then I campaigned twice in Spain [181 and 180 BC] … I was brought home by Flaccus along with the others whom he brought with him from the province to take part in the Triumph because of their bravery. Four times within a few years I held the rank ofprimus pilus [centurion of the first century of the triarii]. Four and thirty times I was rewarded for bravery by my commanders. I have received six civic crowns. I have served out twenty-two years in the army and am more than fifty years old.54

Ligustinus, who had six sons and two married daughters, was petitioning for further office or promotion, and, on the strength of his record, was made primus pilus, senior centurion, in the First Legion.

With an officer corps of the quality represented by Ligustinus, formed of men whose life was soldiering, who entertained no expectation of rising into the governing class, and whose ambitions were entirely limited to those of success within what could be perceived, for the first time in history, as an esteemed and self-sufficient profession, it is not surprising that Rome’s boundaries came to be extended from the Atlantic to the Caucasus; it succeeded, by whatever means, in transforming the warrior ethos of a small city state into a true military culture, an entirely novel Weltanschauung, one shared by the highest and the lowest levels of Roman society, but rooted in and expressed through the values of a separate and subordinate corporation of specialists. Theirs was not a privileged life by any material test. For all the mechanistic efficiency of the legion in battle, Roman warfare remained a bloody and intensely dangerous business. The centurion, quite as much as the legionary, fought at close range to the enemy, often hand to hand, and accepted the danger of wounding as an inescapable hazard of the life he had chosen. Julius Caesar, for example, writing of his battle against the Nervii on the River Sambre in modern Belgium, in 57 BC, describes the critical moment:

The soldiers were crowded too closely together to be able to fight easily, because the standards of the Twelfth Legion had been massed in one place. All the centurions of the first cohort had been killed, together with its standard bearer, and its standard had been lost. In the other cohort almost all the centurions were dead or wounded and the chief centurion, Sextius Baculus, a very brave man, was so exhausted by the wounds, many and severe, that he had suffered, that he could hardly stand up.55

This graphic depiction of the reality of legionary warfare, in which the unvarying daily order of the camp, with its set duties of guards and fatigues and the regular comforts of the kitchen and the bath-house — no different at all from the routines maintained by European garrison armies a hundred years ago — could be suddenly interrupted by confrontation with a yelling crowd of unshaven and unkempt strangers, perhaps daubed with paint, brandishing deadly weapons, reeking of dirt and fear and sweating with the intense exertion of muscle-power warfare, conveys without the need for further demonstration that the Roman professional soldier did not serve for the monetary rewards enlistment brought him.56 His values were those by which his fellows in the modern age continue to live: pride in a distinctive (and distinctively masculine) way of life, concern to enjoy the good opinion of comrades, satisfaction in the largely symbolic tokens of professional success, hope of promotion, expectation of a comfortable and honourable retirement.

As the empire grew and as the army revised its terms of enlistment to admit recruits who were not of Italian origin, whether as legionaries or as cavalry or as light infantry auxiliaries, the military profession became multinational in character, its members united largely by the duty they owed to Rome. In a remarkable survey that was made of the careers of ten Roman soldiers who died in the service of the empire during the first two centuries AD, as revealed by their gravestones, we find a cavalryman from Mauritania (modern Morocco) who died on Hadrian’s Wall; the standard-bearer of the II Legio Augusta, born at Lyon, who died in Wales; a centurion of the X Legio Gemina, born at Bologna, who was killed in Germany at the disaster of the Teutoburg forest; a veteran of the same legion born near the headwaters of the Rhine, who died on the Danube at modern Budapest; and a legionary of the II Legio Adiutrix, born in modern Austria, who died at Alexandria.57 Perhaps the most touching of funerary records that show how widely the legions were recruited comes from the gravestones of a wife and her soldier husband found at opposite ends of Hadrian’s Wall: she was a local girl; he had been born in Roman Syria.

It was a regular army, nevertheless, made for regular, not dynamic, empire-building. The process by which the legions came to serve at such distance from the Roman army’s birthplace and to embrace so wide a range of recruits as members — many from localities which lay in ‘barbary’ at the start of Rome’s rise to empire — began in earnest during the Punic wars with Carthage. That city, a colony of the Phoenicians, first fell into conflict with the Romans when the latters’ success in subduing their Italian neighbours drew them south to Sicily, which Carthage regarded as within its sphere of influence; Rome’s confrontation with Pyrrhus, also an enemy of Carthage, weakened its position in the island. In 265 BC the two powers found themselves at war over it, and the war rapidly extended, by both land and sea, until the Carthaginians were obliged to concede defeat and the establishment of Roman control over western Sicily. While Rome added Corsica and Sardinia to these beginnings of its overseas empire, and made its first inroads into the lands of the Gauls, Carthage responded by campaigning along the Mediterranean coast of Spain, against cities that were Rome’s allies. The siege of Saguntum in 219 BC brought on war afresh; it lasted for seventeen years, ended in Carthaginian defeat only after Rome had stared catastrophe in the face, and established the Romans as the dominant power in the Mediterranean world.

Carthage, with a large fleet, depended principally on mercenaries to provide her army, recruited from the North African coast and paid from the revenues of her trading empire, whose connections extended as far as the tin-producing regions of Britain. Fortuitously, she was during the Second Punic War to produce two commanders of outstanding ability, the brothers Hannibal and Hasdrubal, whose powers of leadership and tactical innovation transcended the limitation which the mercenary character of their soldiers imposed on their capacity to operate at long range from base. Hannibal opened operations with what was to become one of the most famous campaigns in history — his lightning march from Spain through southern Gaul, across the Alps and into central Italy, bringing with him a train of elephants. Defeating one Roman army at Lake Trasimene in 217 BC, he bypassed Rome, found allies in the south, rode out a delaying campaign by Fabius Maximus and took up a position in which he hoped to be joined by the Macedonian King Philip V, one of Alexander’s successors. The Romans had now lost patience with Fabian tactics, and in 216 BC their field army advanced to contact with the Carthaginians near the Apulian town of Cannae. There on 2 August, sixteen legions, comprising some 75,000 troops, advanced to the attack. Varro, the Roman commander, had put his infantry mass in the centre, with cavalry at each wing, the standard classical deployment. Hannibal reversed arrangements, leaving his centre weak but massing his best infantry on either flank. When the Romans came forward, they were swiftly enveloped, their line of retreat cut off by a cavalry charge across their rear and the fugitives, to the number of 50,000, massacred as they fled. It was from the example of Cannae that the nineteenth-century French tactical analyst Ardant du Picq first proposed the important perception that it is in retreating that an army exposes itself to disabling losses.

By a stroke of diversionary strategy the Romans were able to ride out the disaster at Cannae. At home new legions were formed from the propertyless, normally exempt from service, and even from slaves, which provided enough force to confine Hannibal to southern Italy, where the Carthaginians had allies. In Spain, where the consul Cornelius Scipio had presciently stationed two legions to prevent Hannibal’s drawing reinforcements from that region, the Romans went over to the offensive. In 209 Scipio’s son, later to be famous as Scipio Africanus, launched a lightning attack against Cartagena, where the atrocities his troops committed had the effect of drawing the city’s uncommitted neighbours to his side. When Hasdrubal beat a fighting retreat to the Adriatic, along the route his brother Hannibal had followed eleven years earlier, he was run to ground and defeated at the River Metaurus. His successor in Spain, another Hasdrubal, suffered the indignity of being beaten in a battle where Scipio applied against him the tactics that had won Cannae. This setback, from which Scipio profited to cross to Africa, impelled Carthage to call Hannibal home, and at Zama, in modern Tunisia, their two armies met in 202 BC. A Carthaginian elephant charge was nullified by the chequerboard formation in which Scipio disposed his troops; when he launched them in a counter-attack, the Carthaginian army was overwhelmed and Hannibal fled the field.

The final destruction of Carthage was to wait fifty years, during which Rome’s military energies were consumed by interventions in Greece and the rest of the Hellenistic world. By 196 BC the Greek cities accepted a Roman protectorate, and when the Hellenistic kingdom of Syria intervened to reverse events, Rome transferred the legions first there and then to Asia Minor, most of which shortly fell under its control; Ptolemaic Egypt, most important among the surviving kingdoms once controlled by Alexander’s generals, also fell by 30 BC.

By that date the most famous of Romans, Julius Caesar, had added Gaul to the empire, in a series of campaigns that lasted from 58 to 51 BC. Following its earlier expulsion of the Gallic tribes from northern Italy as early as 121 BC, Rome had gained a foothold in Gaul by expanding its province in Spain. In 58, to forestall the first recorded large-scale migration the Romans had encountered, that of the Helvetii from modern Switzerland, Caesar set up blocking positions in the Rhône valley and accepted help from the Gauls to resist the invasion. Having defeated the Helvetii, he now found his new area of control threatened by another invasion, that of a Teutonic tribe under Ariovistus, and he marched north to the Rhine to turn it back. His success, though welcome to the Gauls of the south, alarmed those of the north, whose tribal systems extended across the Rhine into Germany. Against these extremely warlike people he fought for four years, interrupted by expeditions against the Veneti of Brittany and their Celtic cousins in Britain (56–4 BC), but eventually he succeeded in imposing nominal peace throughout Gaul. Then, in 53 BC, the pacified Gauls rebelled en masse in a desperate effort to avoid incorporation into the empire and, under the leadership of Vercingetorix, obliged Caesar to repeat his efforts. This final stage of the Gallic wars, fought against an enemy who had learned much from Roman methods, lasted a year, when Vercingetorix retired into a vast fortified camp at Alesia, near the source of the Seine. This decision was a mistake; the Romans had formidable experience of and skills in siege warfare — it may be that some of the techniques they knew had been transmitted to them at several removes from their Assyrian inventors, via the international market in military science that had permeated the Middle East for centuries — and they quickly insulated the Alesian camp from any prospect of relief by constructing an even larger encirclement of fortifications (lines of ‘circumvallation’ and ‘contravallation’), each about fourteen miles in circumference, to enclose it. Legionaries were masters of the spade; on the march in hostile territory, a legion automatically threw up for itself an entrenched camp of uniform pattern each night. When a relieving Celtic army appeared, estimated to have been a quarter of a million strong, Caesar supplied his 55,000 out of the stores he had accumulated within his own fortifications, held the attackers at bay, and persisted with his investment of Vercingetorix’s position. Eventually, after three attempts to break out, the Gallic chieftain offered his surrender, was taken to Rome for Caesar’s triumph, and then executed. With his death, native resistance to the inclusion of Gaul within the Roman empire collapsed.

Greek helmet and cuirass of the Eighth Century BC, the oldest discovered suit of hoplite armour. Bronze was preferred for bodily protection long after it was supplanted by iron in the manufacture of weapons.

A hoplite of the Sixth Century BC his shield has not yet assumed the distinctive bowl shape, in which the wounded — or dead — warrior was brought back from the battlefield.

Hoplites preparing for battle, from a vase painting of 515 BC; the shield protected the stomach and thighs from spear thrusts when the massed ranks closed.

A Roman oared warship, descendant of the Greek trireme, advancing to battle; its prow is armed with a ram and its upper deck manned by marines.

Legionaries crossing a bridge of boats, from Trajan’s Column, Second Century AD; the Legions, like the Assyrian army, marched with a bridging train on campaign.

A centurion of the XX Legion, one of the four which conquered Britain, who died at Colchester about 45 AD. He carries his vinestick of authority.

Terracotta of a barbarian enemy of Rome from the Puy-de-Dôme, Third Century AD; a forerunner of the tribesmen who overwhelmed the empire in the Fifth Century.

A Frankish horseman on his warhorse, in chain mail and with shield and lance as depicted by a Scandinavian enemy — who was unaware of the stirrup — in the Eighth Century.

Crusaders in chain mail charging Muslim horsemen, Fourteenth Century; in practice, Middle Eastern light horsemen avoided the direct clash of arms.

A late Fifteenth-Century depiction of escalade at the siege of a fortified city; the soldiers wear plate armour but there are cannon in the entrenchments.

The earliest known representation of a cannon, 1326; the gingerly application of linstock to touchhole indicates how unfamiliar the weapon was.

The beginnings of mutuality between man and the gunpowder weapon, about 1400; a century later the soldier would be putting it to his shoulder.

Galleys of the Knights of Malta (the Hospitallers of the Crusades) in battle with the Ottoman fleet, early Seventeenth Century; land warfare at sea.

The Great Harry, one of the first ships built — for Henry VIII of England in 1514 — to fire cannon broadside; they would dominate naval warfare until the 1850s.

A Seventeenth-Century manual of arms; step-by-step procedure in the handling of the musket by ranked men was essential to avoid fatal accidents.

Siege cannon, hitched to limbers drawn by trains of horses, on the way to a position, 1702; cannon such as these inaugurated the artillery revolution two hundred years earlier.

A gunpowder mill, from The Universal Magazine, December, 1773; the monopolisation of gunpowder production by governments was a key to the rise of the modern state.

The battle of Williamsburg, May 5, 1862, American Civil War; despite the North’s material superiority. Southern musketry and digging saved Richmond in this Peninsula Campaign.

Cannon manufacture in the American Civil War; the Americans were the first industrial nation to apply mass-production methods in arsenals.

Northern railroad soldiers at work on the Orange and Alexandria line during the American Civil War; railroad construction — and destruction — underlay the North’s victory.

Alfred Krupp’s trial range at Meppen, 1879; his steel cannon revolutionised artillery equipment in the years before the First World War.

A British trench sentry on the Somme, 1916, with sleeping comrades; even routine trench warfare was dangerous and exhausting.

A German Junkers 87 dive-bomber launches its bomb at a French tank during the blitzkrieg of 1940, a portent of the air domination of the battlefield.

An Atlantic convoy bringing war supplies from America to Britain, 1943; the escorting aircraft was the instrument of the U-boats’ defeat.

Flying Fortresses (B-17s) in the strategic air campaign against Germany, 1944; the condensation trails are from their escorting fighters.

Test explosion of an atomic bomb at Bikini atoll, July 25, 1946; no military thinker has explained how nuclear warfare might be a continuation of politics.

The Roman empire was now almost as large as it would ever be in the west and had achieved nearly its fullest extent in Africa and the Near East; only on the frontier with the Middle East, where the kingdoms of Parthia and Persia were still powerful enough to contest control with Rome, would there be conquests still to be made. The very success of imperial expansion had thrown the social and political order at home into crisis, however. The relentless search for recruits, particularly among the Italians to whom incorporation in Roman territory had not brought the privileges of citizenship, and the growing power of consuls returning victorious from their annual campaigns to confront the magistrates in Rome with demands for money and authority, rendered the old systems of legionary enlistment and elective government increasingly obsolete. There had been a foretaste of trouble at the end of the second century BC when the brothers Gracchus had attempted to reduce both the burden of the military levy and the independence of the military authorities. Trouble became serious in 90 BC, when the Italian non-citizens revolted against the levy and were pacified only by grant of full citizenship. The difficulties in supplying the legions with manpower nevertheless persisted, even though there had been an effective dispensation with the ancient property qualification at the end of the first century, when the consul Marius opened the ranks to volunteers from the lowest census class. This measure paradoxically heightened the developing conflict between campaigning consuls and the city’s political class, since it attached landless legionaries more closely to a commander, identified their interest with his (particularly if, as Marius did, he promised land as a reward for successful service) and thus strengthened the hand of generals against senate and magistrates.58

The crisis came to a head on Caesar’s completion of his Gallic conquests. When he sought to prolong his period in command, the senate refused him; when he left his province, outside which his powers of command legally lapsed, at the head of the XIII Legion to return to Rome, he effectively threw down a challenge to civil war. The war lasted seven years (50–44 BC) and was fought as far afield as Spain, Egypt and Africa, as the senate found legions and generals, notably Pompey, to resist Caesar’s rebellion. It culminated in his triumph and then, at the hands of principled opponents of dictatorship as well as disgruntled enemies, in his assassination. In the struggle for power that followed, Caesar’s nephew, Octavian, overcame all opponents in a renewal of the civil war and in 27 BC, having already been granted the title of Emperor (though nominally ‘Princeps’, first citizen) by a compliant senate, added to it that of Augustus. Republican forms, though preserved in name, were effectively extinguished from that moment and henceforth Rome was an empire in substance as well as extent.

The imperial system resolved the anomalies inherent in the attempt to govern a military state through the competitive politics of an exclusive and no longer representative electoral class. The first effects were felt in the army itself. Augustus found it grossly swollen by civil war, to a size of half a million men, many of them little better than mercenary followers of rival commanders; he sharply reduced its numbers and stabilised it at a strength of twenty-eight legions. To assure the security of the central government against a repetition of Caesarism, he formed a new force, the Praetorian Guard, to garrison Rome. The field army was distributed largely to the frontiers, with the heaviest concentrations on the lower Rhine, opposite Germany, from which population pressure was already felt; on the upper Danube, another region disturbed by the barbarians; and in Syria; smaller garrisons were maintained in Spain, Africa and Egypt. Equally important were the alterations he introduced into the basis of service. The fiction of the militia obligation was abolished and the legions became professional by enlistment. Preference was given to citizens, but suitable non-citizens were granted citizenship on recruitment; the term of service was fifteen years (often twenty in practice), during which legionaries were forbidden to marry — though families naturally, if illegally, attached themselves to the camps; pay was fixed and regular and, on discharge, the veteran received a retirement gratuity sufficient to provide him with a living. New taxes, actuarially calculated, found the large sums necessary to settle the veterans and so to provide the serving soldiers with a consequent incentive to loyalty and good conduct.

The numbers in the Augustan army settled at about 125,000 men. A similar number served in the legions’ auxiliary units of cavalry and light infantry. Rome had employed such units since the start of the Italian conquests, but the auxiliaries had not been citizens and their terms of service had been irregular. Henceforth, certainly from the reign of Claudius, the successor of Augustus, they were properly paid, but the great inducement was that, at the end of twenty-five years’ service, the discharged soldier received a grant of citizenship; so, too, since he was allowed to marry, did the sons of one wife, whenever born. These provisions greatly improved the quality of auxiliary troops, some of which were to perform so well that their members would be granted citizenship en bloc. As time went on, moreover, the cavalry wings and infantry cohorts ceased to be recruited at the point of service (a tendency that assimilated their quality much nearer to that of the legions), passed from the command of local chiefs to imperial officers, and were posted for duty anywhere in the empire.59

Augustus did most to secure the future reliability of the army by the arrangements he made for its command. Under the republic the proconsul of a province had commanded the legions within it. Augustus appointed himself proconsul of most of the provinces, so that he directly commanded their legionary garrisons, while decreeing that for the rest, to which the senate still appointed its nominees to govern, the legions came under his command also, through legates who were his personal representatives. To administer and finance this complex and highly centralised system, Augustus created an imperial civil service, staffed at its head by members of the political class, for whom it provided welcome responsibilities as well as state salaries. To these imperial officers fell the duty of raising taxes to support the provincial administrations and garrisons, to make the transfers to the imperial treasury and, in Egypt and Africa, to buy and collect the grain which supplied the city’s families with free rations; 400,000 tons were imported each year.

This Julio-Claudian system, as historians call it, served well under his immediate successors, but contained unperceived perils. With a disputed imperial succession, or defeat in war, authority tended to revert to the army, on which the whole structure rested. The Roman empire’s success committed it inevitably to go to war, since it could not tolerate disorder on its borders, while the growing prosperity it fostered encouraged envious outsiders to seek entry by force. Disorder was the principal danger in the east, where ancient kingdoms and the surviving rival empires of Parthia and Persia resented Rome’s efforts to establish a stable line of control; intrusion was the danger in the west, along the Rhine and Danube, where the great movements of population, impelled by pressures from the steppe, were already being felt during the first century AD.

In AD 69 the predictable crisis supervened. There had been military successes under the Julio-Claudians. Britain (invaded in AD 43) had been added to the empire and Armenia had in 63 accepted Roman suzerainty. Equally there had been revolts, notably in Germany, where Arminius had destroyed a Roman army in the Teutoburg forest (AD 9), and in Judaea, where the Jews rose against Roman rule in 66. In 68 the eccentric, perhaps mad, reigning emperor, Nero, lost his soldiers’ confidence and was overthrown by military insurrection; this led to civil war, competing claims to the succession and the eventual emergence of a soldier-emperor, Vespasian, not of Julio-Claudian birth. Able and cautious, he restored imperial stability but, as a military usurper, lacked legitimacy. That was revived by his eventual successor Nerva, who established the principle of appointing strong rulers by the process of formal adoption of a promising heir. Thus four adoptive successors, Trajan, Hadrian, Antoninus Pius and Marcus Aurelius, were all gifted administrators and successful commanders. Under these Antonine emperors (AD 98–180) the Roman armies won a string of victories and added Mesopotamia, Assyria and the trans-Danubian province of Dacia (modern Hungary) to the empire.

The success of the Antonines derived from their adoption of a policy of military stabilisation wherever it could be achieved, which meant everywhere except on the open border with Parthia and Persia. This has been called ‘a grand strategy based on preclusive security — the establishment of a linear barrier of perimeter defence around the Empire’.60 Historians differ bitterly over the complexities of the strategy. Some deny that it had any basis in Roman consciousness, and that the apparent drive to reach and hold ‘scientific’ frontiers, on the Rhine, Danube, north British highlands and edge of the Sahara, signified by the building of the fortifications whose sometimes massive relics still mark their outline, reveals nothing more than the desire of local commanders or visiting emperors to establish police posts and customs control at the edge of a zone of formal administration.61 Those who hold such views deserve attention, since their knowledge of the details of Roman military policy is extensive and exact; the strength of their views is also reinforced by the terms in which they characterise the Roman military outlook: always informed by ‘a desire for glory’ rather than by strategic theory. That perception rings true. Clausewitz and his contemporary ideologues may have been inspired by Roman military practice, but the notion that Roman warmaking, any more than Alexander’s, was Clausewitzian in essence bears very little weight. However logical his analysis of particular military situations, Alexander was drawn eastward by vainglorious impulse; Rome, perhaps also vainglorious, certainly entertained no conception of ‘war as the continuation of politics’ since it granted to none of its enemies, not even the Parthians or Persians, the dignity of civic status. Like the Chinese, the Romans divided the world into civilisation and the lands beyond its sway, and while they sometimes of necessity resorted to diplomacy (in their dealings with the Armenians and other old-established kingdoms, for example), they did so for reasons of expediency alone, not as one state treating with its equivalent. There was, indeed, no reason for them to do so. Not only by the tests of military and bureaucratic organisation did the Romans surpass every other people against whom their borders abutted. The ‘idea’ of Rome, which in AD 212 extended citizenship to all free men within its imperial boundaries, had no parallel elsewhere; nor did the extraordinary infrastructure of roads, bridges, aqueducts, dams, arsenals, barracks and public buildings by which Roman military power, civil administration and economic life were sustained.

Nevertheless, the existence of Rome’s fortified frontiers, like much of China’s Great Wall, is a fact. The Chinese learned that the building of a fixed line of defence does not of itself guarantee security, which can be maintained only by the simultaneous execution of a ‘forward’ policy, as by the T’ang into Dzungaria and the Manchu on to the steppe; the failure of the intervening dynasties of non-steppe origin to pursue or succeed in such a policy did not invalidate the building of the Wall in the first place, since it marked the outline of the cultural zone that all Chinese governments sought to preserve. Equally, the retrospective denials by some modern scholars that the Roman effort at fortification was a subordinate and secondary characteristic of the empire’s real strategic purposes stumbles on the stones of the fortifications themselves. It may well be that in the first two centuries after Augustus the empire depended on the strength of the legions, variously deployed, to sustain security by indirect means. That is the view of Edward Luttwak, who suggests that the policy of the Julio-Claudians, who were still fighting wars of expansion, was to use the legions as a source of ultimate guarantee for a defence organised in first line by newly subdued clients, such as those in northern Greece, Asia Minor and Africa; while under the Antonines the legions were distributed at the frontiers to garrison barriers which then became the primary obstacle zone on which external threats were intended to break. Particular crises, he argues, were met by the concentration at the point of danger of legions withdrawn from borders where peace prevailed. His view is disputed by others who variously claim that the Romans remained expansionist on the frontiers where enemies challenged their power, notably those with Parthia and Persia, or that the army’s main preoccupation was with local disorders which had their roots in habits of endemic brigandage, piracy or the indisciplines of transhumant herding tribes.

Nevertheless, no one denies that from the third century AD onward, when population pressure in the west and the strains of war with Persia in the east intensified, the identification of the legions with the fortified frontiers became absolute. There was a rationalisation of borders, particularly on the Danube, where the province of Dacia was abandoned in 270, on the River Rhine, on the lower Nile, where the Romans found the Numidians as implacable as the pharaohs had done, and in Africa, where parts of Mauritania were evacuated in 298. On the shorter lines, however, the legions were to fight for another century, and Roman strategy centred on the protection of the internal territories whose integrity the fortified frontiers defined. That being so, it is not factitious to argue that, even if in diluted strength, the outline of the frontiers, which shifted little between the accession of Augustus in the first century BC and the abandonment of Britain at the beginning of the fifth AD, exerted throughout a determining influence on the Roman military outlook. Historians with a particular knowledge of a period or a province, even of the Roman empire as a whole, may be able to show explicit inconsistencies in the view, perhaps bequeathed to us by Gibbon, that Rome saw itself as the still centre of a world of barbaric disorder. But to do so is to overlook the influence that the psychology of a professional army exerted on the imperial policies of the governments it served. Once frontiers are defined by fortifications which then become the permanent places of garrison of formal and named units, or at least familiar stopping-places through which such units rotate, they take on a symbolic significance for the soldiers who defend them; the emergence of such a symbolism is easily discernible in the history of the Roman army when, for example, we find that the VI Legio Victrix, which arrived in Britain about AD 122 from the Rhine, was still there sixty years later, that III Legio Cyrenaica, raised by Julius Caesar on the Nile, was still based in Egypt in the third century, and that two cavalry regiments, Ala Augusta Gallorum Petriana and Ala I Pannoniorum Sabiniana, raised respectively in Gaul and Pannonia (modern Hungary), served from the second to the third centuries on Hadrian’s Wall, the latter throughout at what is today Stanwix.62 The examples elaborate: between AD 69 and 215, III Legio Gallica was in Syria, from AD 85 to 215, II Legio Adiutrix was in Hungary, and from AD 71 to 215 VII Legio Gemina was on the Rhine.63

Within an army whose backbone was supplied by a body of professional soldiers on whose tongues circulated from generation to generation the litany of the legions’ cantonments and the lore of the life lived there, it is impossible that the soldiers’ consciousness did not eventually come to be circumscribed by the geography of the frontiers. There was, of course, much to distract their attention from imperial defence, notably the recurrent disputes over the imperial succession which, during the third century, called legion into conflict with legion in the service of usurpers and provincial pretenders who laid claim to it. The reorganisation of the garrisons under Constantine (AD 312–37), who succeeded to the imperial title by victory in one of these civil wars, withdrew the legions into several central reserves, reduced them in size and added sizeable formations of cavalry to the army.64 These changes drastically altered the composition of the army, diluting for good the strength of the infantry foundation on which it had rested since republican times. It remained, nevertheless, an imperial army, supported, if with greater difficulty in their collection, by imperial taxes, and still dedicated, though at a greater distance from base, to the defence of the frontiers. The quality of the auxiliaries, left by the Constantian reforms in uncomfortable isolation on the ever more contested borders, declined as a result of their detachment from contact with the legions; increasingly these units of limitanei were formed from locally enlisted peasant militias, who were farmers before they were soldiers. The military worth of the regulars remained, nevertheless, formidable.

After Diocletian (284–305), the empire was divided for administrative purposes into western and eastern halves, with a consequent and progressively separative effect on their military forces. But the next and eventually disabling crisis of the imperial armies was not felt until the fifth century. Despite the disasters of the Persian campaign of 363, in which the emperor Julian the Apostate was killed, and the catastrophe of Adrianople (396), in which Valens died at the hands of the Goths, order within the empire and the defence of its borders was restored by the titanic efforts of Theodosius, who reunited the eastern and western halves and waged a succession of campaigns to repel the outsiders from its territory. Nevertheless, as we have seen, it was Theodosius who took the fatal step of compromising the Romanity of the army by accepting under his command large units of barbarian ‘federates’ who served, not as the auxiliaries of old had done in units raised and officered by imperial officials, but as allies under their own leaders. This step, once taken, could not be withdrawn. Throughout the first half of the fifth century Teutonic soldiers poured into the western empire, and, though the imperial structures there remained nominally in place, and local generals such as Constantius or Aëtius retained sufficient force under command to confine some tribes to limited areas of conquest, and at times even to set barbarian against barbarian, control of the frontiers had to be abandoned altogether, while control within was feeble and erratic. The ‘Roman’ armies of Constantius and Aëtius were Teutonic in composition, carried Teutonic weapons, lost all semblance of legionary drill, and even adopted the German warcry, the baritus.65

In the face of Attila and the Huns, some of these barbarian invaders, who had suffered at Hunnish hands outside the empire, came to Aëtius’s aid; they formed a large proportion of his army at Châlons in 451. While that victory spared Gaul, and perhaps Rome, from devastation by a horse people, Italy and the capital now came under threat from another direction. Gaiseric, leader of the tribe of Vandals who had crossed Gaul and Spain to found a kingdom in North Africa, took to the sea, seized Corsica and Sardinia and from that base captured and sacked Rome in 455; a counter-offensive mounted against him by Leo, the eastern emperor, ended in failure; and the Vandals established a piratical regime that controlled Mediterranean waters from their bases in Sicily and Africa; it was carried on by Saracen and Barbary successors for a thousand years. In Gaul and Italy power passed to three German chieftains, Ricimer, Orestes and Odoacer, who set up a succession of puppet emperors. One of them, Marjorian (457–61), actually reasserted a brief imperial authority in southern Gaul but was then forced off the throne. In 476 Odoacer, who disposed of the largest force in Italy, nominally a Roman army owing obedience to the puppet emperor Romulus, defeated Ricimer in a struggle for power, deposed Romulus and proclaimed himself not emperor but king. The senate, which still survived in shadow form, returned the imperial regalia to the eastern emperor at Constantinople; the Roman army in the west had already long ceased to exist.66

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