The rise of the professional army

The second half of the second century вс was a sorry chapter in Roman military history. Viriathus and the Numantines humiliated successive Roman armies in Spain, and the only major defeat of the Macedonian wars occurred in 149 вс when a motley army of Thracians led by a pretender to the throne defeated a Roman force and killed the praetor in command. Rome had provoked the Third Punic War out of fear that Carthage was rebuilding her strength, but the opening of the campaign in Africa saw badly trained and poorly led Roman soldiers suffering one disaster after another. The Romans eventually won all of these conflicts, and the utter destruction of Carthage in 146 вс conformed to the trend of Roman warfare becoming simultaneously more brutal and less successful. The atrocities committed in Spain in the 150s have already been mentioned, and it is probable that Polybius’ description of the violence of the Roman sack of a city, where not only people but even dogs were slaughtered and mutilated, was most typical of this period. This ferocity was a product of frustration at the difficulty of achieving complete victory, and fear produced by many unexpected defeats.

Nearly every campaign in the rest of the century followed the same pattern of early disasters before a prolonged effort brought victory. The war with the Numidian king Jugurtha (112—106 вс) resulted in scandals as troops deserted en masse, and commanders were found to be either incompetent or had been bribed by the enemy. The first Roman army sent to the war surrendered and suffered the humiliation of being sent under the yoke. The migrating Germanic tribes of the Cimbri and Teutones threatened Italy itself after they had smashed a series of Roman armies sent against them. The casualties at Arausio in 105 вс were on the same scale as those at Cannae, with allegedly eighty thousand men falling. Alarm at the prospect of a repeat of the Gallic sack caused such panic that for the last time in their history the Romans performed a human sacrifice, burying alive a Greek and a Gallic man and woman in the forum.

A major factor in these disasters was Roman overconfidence. The defeat of the kingdoms of the Hellenistic world, the conquest of Cisalpine Gaul and the wars up to Gracchus’ settlement in Spain were all fought by armies and commanders raised in the hard school of the war with Hannibal. The intense campaigning of the first quarter of the century was followed by a relatively peaceful twenty-five years, broken only by the Third Macedonian War. Gradually the collected experience of the generation of the Second Punic War was lost. A new generation grew up who had forgotten that the earlier successes were the result of careful preparation and training, and assumed that victory came as a matter of course, simply because they were Roman. Fewer of the ordinary soldiers were veterans and many of their inexperienced officers either thought that it was unnecessary or did not know how to turn them into effective units. If soldiers had served in other campaigns they were as likely to have experienced defeats as victories. Many of the successes of Viriathus and the Numantines were won over more numerous Roman forces.

The changing situation placed a great strain on the militia system as permanent garrisons needed to be maintained in many of the overseas provinces.

The Gallic bill town of Roquepertuse was sacked by the Romans in the 120s вс. It included this important shrine, built in stone like the Greek temples of nearby Massilia, but decorated with severed heads set into niches in the wall. Head-bunting was practised by many of the peoples of Iron Age Europe, but was especially important to the Gauls, whose religion invested the head with great importance. A similar shrine has been excavated at the nearby town of Entremont, also taken by the Romans in this period during the creation of the province of Gallia Narbonensis, modern-day Provence.

Below: This statue of a young, clean-shaven and short-haired Gallic warrior found at Vacheres in France represents one of the best- equipped members of a tribal war band. He carries an oval shield, has a long, slashing sword on his right hip and wears a coat of mail armour.

Below: This battle scene from the Arch of Orange commemorates the defeat of one of the occasional Gallic rebellions that occurred in the seventy years after Caesar's conquest. Probably dating to the reign of Tiberius, it provides an excellent depiction of the equipment worn by legionaries and auxiliary cavalrymen in the early first century ad.

The old ideal of the citizen farmer, who owned enough property to equip himself as a soldier and served for a campaigning season before returning to till his fields, was under threat. Such a man faced ruination if he was unable to tend his land for a decade of service in a legion in Spain. In the latter part of the second century Romans believed that the numbers of citizens owning enough land to qualify them for military service was dwindling. Increasingly large stretches of Italy had been swallowed up by great estates (or lutifundia), owned by aristocrats enriched by Roman expansion and worked by gangs of slaves captured in foreign wars. Scholarly opinion remains divided over the real extent of this problem, some claiming that free yeoman farmers were flourishing in some parts of Italy, but it is clear that the Romans believed their previously inexhaustible supply of military manpower was under threat. Even if the number of potential recruits had not fallen by that much, the numerous setbacks suffered by Roman armies may well have created the impression that their quality had declined.

Traditionally, Marius, the general who won the war with Jugurtha and then defeated the Cimbri, has been credited with converting the Roman army from a militia raised through universal conscription, into a professional army recruited from volunteers. Certainly, before leaving to take command of the army in Africa, Marius appealed for volunteers from the class known as the capite censi (citizens who did not possess enough property to make them liable to service in the legions). More recently, scholars have interpreted the change as occurring gradually, pointing to earlier measures to reduce the minimum qualification for service and equip soldiers at the state’s expense. There do appear to have been some men who viewed military service as a career before these changes. Livy tells us of one such ‘professional’ soldier, Spurius Ligustinus, who first enrolled in the army in 200 вс and had served twenty-two years in Greece and Spain before his re-enlistment for the Third Macedonian War. Highly decorated, Ligustinus had served all but two years as a centurion, holding increasingly senior posts, culminating in that of primus piltts.

A Roman copy of a Hellenistic original, the Dying Gaul is one of the finest pieces of Classical art, symbolizing both the splendour of barbarian races and their inevitable defeat by civilization. The long moustache and the limed hair, combed up to create an intimidating, spiky effect, are common in literary descriptions of Celts, as is the heroic nudity.

This coin commemorates the Roman victory in the Social War (90-88 вс), the last great rebellion by the Italian allies, or socii. It was a fierce struggle, fought between similarly equipped and trained armies, which the Romans won as much by conciliation as military force.

His pattern of service would not have been much out of place in the army of the Empire, and in fact Livy presents his career in a style suspiciously similar to the memorial inscriptions that were beginning to become popular with soldiers in the late first century вс. Ligustinus is presented as the ideal farmer soldier, since Livy takes care to point out that he still farmed the plot of land he had been left by his father, where his wife had borne him six sons and two daughters. What is interesting is that this smallholding was not of sufficient size to have rendered him liable to military service at all, and that his army service had been voluntary. How common such semiprofessionals were is impossible to estimate, nor can we know whether most such men were to be found among the centurionate rather than the rank and file.

Although we cannot precisely trace the process of change, the character of the army had changed irrevocably by the first century вс. The soldiers were now recruited mainly from the landless poor, men for whom military service was a career rather than a temporary interlude in their normal occupation. After the Social War, which saw the last great rebellion of some of Rome’s Italian allies, Roman citizenship was extended to much of the Italian peninsula. The old alae disappeared and all Italians were now recruited into the legions.

These legions became more permanent, and began to develop a distinct identity, a process accelerated by Marius’ replacement of the five standards of a legion (a boar, a wolf, a horse, an eagle and a minotaur) with a single silver eagle. All the old distinctions based on property and age were swept away. The cavalry and velites disappeared and all legionaries were now heavy infantry armed with the pilum and gladius, wearing mail armour, a bronze helmet and carrying a long, oval shield. The main tactical sub-unit of the legion was now the cohort instead of the maniple. Each of a legion’s ten cohorts consisted of 480 men divided into three maniples, each of two centuries of eighty men commanded by a centurion. The six tribunes were still the senior officers permanently attached to a unit, but it became increasingly common for one of the army commander’s staff, often a senior subordinate or legatus, to be in effective command. The origins of the cohort are obscure. Polybius mentions the term twice, both in connection with Scipio’s army in Spain in the Second Punic War and in an ambiguous passage maybe implying that it consisted of three maniples, as was later to be the case. Livy uses the term anachronistically, but we do know that allied contingents were usually called cohorts, although we do not know their size or internal structure. It is possible that a cohort was a term for any unit smaller than a legion, but larger than a maniple. The cohort appears to have been adopted on an ad hoc basis by the legions in Spain during the second century вс. Much of the campaigning in Spain was on a relatively small scale, when each community might have to be defeated in turn. The old lines of the manipular legion were not effective tactical units for independent operations. The cohort, with its own command structure and with men used to working together, may well have fulfilled a need for forces smaller than a legion.

Marius introduced the eagle (aquila,) as the most important standard of the legion. Initially silver, most were later gilded. The eagle symbolized the pride and corporate identity of the increasingly permanent legions of the professional army.

Below: The backbone of the professional army were the long service centurions, like these on the second-century AD monument at Adamklissi. In undress uniform, without armour or helmets, they wear their swords on the left hip, unlike ordinary legionaries who wore them on the right.

A Legion of ten cohorts

The basic tactical unit of professional legions teas the cohort, each with a paper strength of 480 men, ten of these replacing the thirty maniples of the earlier legion. It is unclear how large the intervals were between units. A depth of six ranks seems to the most common formation for the cohort, and since lines three deep and columns marching six abreast are also recorded, the Roman army's drill was probably based on multiples of three, although depths of four, eight and ten are also recorded.

One century comprising of six ranks of thirteen men plus one centurion in front and an optio (the centurion's second- in-command) behind the rear rank (80 men)

Civil Wars

Rome's greatest period of expansion coincided with and was intimately linked to a series of violent civil wars as various successful commanders vied for supremacy. These campaigns were fought not just in Italy, hut all around the Mediterranean. Caesar failed as dictator to establish a permanent peace and it was only after another thirteen years of war that his nephew and adopted son Octavian managed to bring a lasting peace from civil war to the exhausted Empire.

The new legion was more flexible in every respect than its predecessor. Its usual formation was in the triplex acies with the cohorts deployed in the quincunx pattern, but it could as effectively deploy into one, two or four lines. The uniformly equipped and sized cohorts could be deployed anywhere, unlike the maniples which had been restricted to fixed positions. It was much easier for a commander to control and pass orders to ten cohorts each with their own commanders than it was to do the same with thirty maniples. Roman armies had always become more efficient through long service, training and experience of success, but the greater permanence of the new legions made it easier to preserve this accumulated experience. With professionalization Roman armies began to show far greater ability in the more technical aspects of warfare. Caesar could call from the ranks of his legions men able to design and build bridges or ships, and engineers to prosecute a siege. The average efficiency of Roman armies greatly increased and campaigns were less often delayed when experienced legions had to be discharged and replaced by newly raised units.

There was a major disadvantage to the new system. The professional soldier was recruited from the poor and had no source of livelihood once he was discharged from the army. The Senate refused to take responsibility for demobilized soldiers and made no provision for them or their families, since by law the armies were still supposed to be filled with men of property serving out of duty. The army ceased to represent the whole Roman people under arms and became more and more separate from the rest of society, their loyalty focusing more on their legion than on Rome. Soldiers came to depend on their commanders to provide them with a plot of land on discharge. Charismatic generals such as Sulla, Pompey and Caesar created armies far more loyal to their leaders than they were to the state. This added an increasingly violent dimension to Rome’s competitive politics. The professional armies were as often set to fight against other legions as they were against the foreign enemies of Rome.

Battle of Pharsalus: Phase 1

Pharsalus: phase 1

Our sources for the buttle of Pharsalus in 48 вс are remarkably good and, although vague about the exact location of the battlefield, allow us to represent the armies down to the level of the individual cohorts. Pompey's legions were stronger, but less experienced than Caesar’s. He ordered bis cohorts to deploy ten deep and await the enemy charge at the halt, hoping to keep his raw soldiers in a dense formation and prevent them from running away. Pompey was relying upon his numerically superior cavalry to outflank the enemy right and roll up Caesar’s line. Caesar’s cohorts covered much the same frontage as their opponents, so were probably formed five or six ranks deep. Realizing the threat to his right flank, Caesar took one cohort from the third line of each legion and formed them into a fourth line, angled back and concealed behind his cavalry.

Battle of Pharsalus: Phase 2 and 3

Pharsalus: phases 2 and 3

Labienus led Pompey’s massed cavalry against Caesar's right wing and soon put the enemy horsemen to flight.

However, in the process the recently raised Pompeian squadrons lost their order and merged into one great mass. Suddenly Caesar’s fourth line advanced from behind the main army and charged the milling mass of cavalry, stampeding them to the rear. Elsewhere, the main lines had clashed in a fierce struggle, Caesar’s superbly disciplined men stopping to re-form when they realized that the Pompeian foot were not advancing to meet them and that they had begun their charge too early. As the fourth line swung round to threaten the left flank of the Pompeian legions and Caesar committed his third line to add impetus to the main assault, Pompey’s army collapsed.

The willingness and skill with which the professional legions undertook major works of engineering was one of the most remarkable features of the Roman army. During his campaigns, Caesar was able to draw from the ranks of his army men able to construct great systems of fortifications, build and repair ships, and bridge the River Rhine. Trajan’s Column pays particular attention to the technical skills of the citizen legionaries, and, unlike the non-citizen auxiliaries, more often depicts them working than fighting. Here legionaries construct a fort, working in their armour and with weapons stacked nearby in the proper manner.

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