THE AUGUSTAN EMPIRE (44 B.C.—A.D. 70)

CHAPTER VIII

THE ARMY AND NAVY

I.                THE PROBLEM: THE MAIN FEATURES OF THE AUGUSTAN SETTLEMENT

IN an earlier chapter of this work it was shown that long before the end of the Republic the Roman State was called upon to face problems of government and administration which could not be satisfactorily solved without a complete reorganization of her army and navy, and that under the prevailing political conditions such a reorganization was almost impossible to realize. The military system which had been adequate to the needs of a small State whose wars were confined to Italy and which refused to bring under her direct control a great part even of the peninsula until practically compelled to do so by the Italians themselves, was ill adapted to the conquest and government of extra-Italian provinces. Rome was in no hurry to annex, but circumstances made annexation inevitable, so that by the end of the Republic she was mistress of the greater part of the lands facing the Mediterranean, and had by Caesar’s victories extended her authority to the English Channel and the Atlantic. Many of the provinces of the Republic were exposed to attack from dangerous neighbours. Mithridates and the Parthians resented the presence of Rome in Asia Minor. Macedonia was constantly raided by Balkan tribes, and the invasion of the Teutoni and Cimbri showed the need of protecting the Mediterranean world from the barbarians of central and northern Europe. The problems thus raised were dealt with by the Republic in a very inadequate way. The size of the army was determined by the needs of the moment. In times of peace a province might be practically denuded of troops, and when trouble arose armies had to be improvised in order to meet it. Many disasters might have been avoided had the provinces been at all times garrisoned by a force capable of policing the country and of protecting it against invasion.

Such a situation called for the creation of a professional army consisting of long-service troops and commanded by generals who were primarily not politicians but soldiers. The professional soldier had existed de facto before the days of Marius, and after his reforms there can have been few soldiers who did not serve for a long period and did not look to the State or their general for provision on their discharge. But the size of the army varied according to the military situation, and a soldier on enlistment must have been very uncertain about his future. It is not even clear that he ‘signed on’ for a definite number of years, and there is no doubt that before the time of Augustus the problem of the ‘ex-service man’ was never properly faced.

As regards the officers things were even worse. Provincial commands were regarded as perquisites of the magistracy, with the result that the conduct of wars was often entrusted to men devoid of the necessary knowledge and experience. When the situation became very bad, the ordinary rules were suspended, and an extraordinary command conferred on a Marius, a Sulla, a Pompey, or a Caesar, but such commands were regarded in senatorial circles as abnormal and unconstitutional, and the holder of them tended to be viewed with suspicion. These generals were to a large extent the creators of the armies which they commanded, so that the loyalty of the troops was directed primarily to them. It has been said with truth that ‘so far from there being a State army in the last century of the Republic, there was rather a succession of armies owing loyalty to their respective generals.’

Another defect of the Republican system of army administration was that the burden of military service and imperial defence was borne to an undue extent by Italians. Roman provincial rule was so unpopular that the government did not dare to arm the provincials, even to defend their own homes against invasion. It is true that specialist troops—archers, slingers, and especially cavalry—were provided by certain provinces, but not till the civil war between Pompey and Caesar are provincials to be found in any number in the legions and then only when Italians were not available. Thus when a crisis arose it was necessary to raise an army in Italy and to transport it to the seat of war. This process took time, and in the meanwhile disasters occurred which might well have been avoided had the provincials been equipped with means of defence or an adequate garrison stationed in their midst. So long, however, as Rome’s provincial subjects were treated in such a way that it was hard for them to identify their interests with those of the governing people there could be no question of calling on them to take any large part in the defence of Roman rule against attack. The words used by Cerialis in addressing the revolted Gauls in a.d. 70 could not have been uttered under the Republic. ‘You often command our legions, you govern these and other provinces: there is no narrowness, no exclusiveness in our rule. You benefit as much as we from good rulers though you live far off. Bad emperors attack only those who are near them’. As early as the time of Cicero we find traces of the idea that Rome’s subjects should be grateful for the blessings of the pax Romana, but it is unlikely that this claim found a responsive echo in the minds of men ruled by Verres or Gabinius. It is clear that the well-known tendency of the Romans to avoid revolutionary changes and to retain institutions which a less con­servative people would have abolished had had an unfortunate effect on the army, and that the whole system required to be over­hauled and to be adapted to the new conditions. In no other department was the work of Augustus of such permanent value. The system which existed at his death was modified only in detail by his successors during the first two centuries of our era, and traces of it remained till the last days of the Western Empire.

In this department, as in others, Augustus owed something at least to the example of Caesar. In no army of the Republic had professionalism and efficiency reached such a height as in the force which conquered Gaul and defeated Pompey and his lieutenants. Among Caesar’s officers were men who had little connection with politics and could fairly be regarded as professional soldiers. His legions developed an esprit de corps, rare among the short-lived legions of the Republic, but a familiar feature of the armies of the Principate. Again, by his recognition of the military value of provincials Caesar foreshadowed the practice of the Principate. The chief recruiting-ground of his legions was the Italian province of Cisalpine Gaul, on which the full citizenship was not conferred till 49 b.c., and one whole legion (the Alaudae), recruited in Transalpine Gaul, did not receive the franchise till the period of the Civil War. Even greater use was made of provincials in those sections of his army which were not organized as legions. A large proportion of his cavalry consisted of Gauls and Germans, and when in 49 b.c. he encountered Pompey’s lieutenants in Spain he made use of Gallic contingents led by their own chiefs. His example was followed by his opponents, who indeed, for the campaign of Munda, raised not only auxiliaries but legions among the natives of Spain. At this crisis the old prejudice against the arming of provincials was breaking down, and the way was being prepared for the creation of a regular auxiliary force as a permanent element in the Roman army. Finally, the manner in which Caesar provided for his time-expired soldiers afforded an important precedent. Large bodies of them were settled in the provinces, especially in the south of Gaul. Most of these military colonists must have been men of Italian stock, and the importance of this step in removing the distinction between Italy and the provinces cannot be exaggerated. The Republic had objected on principle to transmarine colonization: C. Gracchus had made himself unpopular by championing an idea which was destined to have a great future.

The steps taken by Augustus to deal with the unwieldy body of troops (consisting of at least sixty legions) which was at his disposal after Actium have been described elsewhere. Soldiers were settled in twenty-eight cities of Italy and in Africa, Sicily, Macedonia, Spain, Greece, Asia, Syria, Gallia Narbonensis, and Pisidia. This process was complete by 13 b.c. and from that date, if not earlier, the total number of legions did not exceed twenty-eight.

Although, as has been said, the professional soldier and even the professional general was not unknown under the Republic, not till the Principate was the army definitely organized on profes­sional lines. The troops raised by Caesar and Pompey and by the Triumvirs had not enlisted for a definite period. They can only have hoped that when their services were no longer required a victorious general would see that they did not starve. But such a system was inconsistent with the ideas of Augustus, to whom the army was not primarily a field force raised for the purpose of a definite campaign, but a permanent garrison intended to protect the frontiers from invasion and to keep order in the provinces. Accordingly in 13 b.c. he decided that legionaries must serve for sixteen years and soldiers of the Praetorian Guard for twelve before they could claim discharge and a definite gratuity. In a.d. 5 the period of service was raised to sixteen years for the praetorians and to twenty for the legionaries, and their allowances fixed at 20,000 and 12,000 sesterces respectively. In the following year the financial burden of this provision for old soldiers, which had hitherto fallen on the emperor’s private revenues, was transferred to a new treasury, the aerarium militare, into which were paid the sums raised by taxes on inheritances and sales. In this way the Roman army became what it was destined to remain, a body of long-service troops.

The government of the Principate claimed and occasionally exercised the right to compel its subjects to serve in the army, but this method of recruiting was unsuitable when military service lasted twenty years or more. Accordingly, compulsion was seldom enforced except at crises, such as the Pannonian Revolt of a.d. 6. Most soldiers were volunteers, of whom an adequate supply was generally available, especially when as a result of the new system families possessing military traditions had sprung up all over the Empire. Enlistment in the army offered good prospects and a secure future. The danger of death in battle was not great at a time when serious wars were rare.

As early as the time of Tiberius it was possible to say that the main strength of the army lay in the non-Italian element. ‘Nihil validum in exercitibus nisi quod externum’. This was indeed an exaggeration, but Augustus, profiting from the experience of the civil wars, had frankly accepted the principle that the defence of the Empire was a task in which provincials might be expected to take an important part. From the beginning the auxilia, whose place in the army was definitely recognized, were recruited entirely in the provinces, and even the legions, especially in the eastern provinces, contained many non-Italians. Nothing did more to create a feeling of imperial patriotism than this confidence shown by the government in the loyalty of provincials. In the Ciceronian age the subjects of Rome were frequently referred to as allies, but the word was not used in anything but a technical sense until the Principate. Provincials learned to feel that they participated in a civilization which it was a privilege to defend against barbarian attacks. The tribes of north-eastern Gaul, for instance, came in time to consider that their spiritual ties were with Italy rather than with their so-called kinsfolk across the Rhine.

Enough has been said to show that Augustus had a clear appreciation of the nature of the problem, and that his solution of it bears every mark of constructive statesmanship.

II. THE LEGIONS

The first task which confronted Augustus after his victory over Antony was to reduce the legionary forces to a manageable size. In the Res Gestae (3) he states that in the course of his reign he settled in colonies or sent back to their own towns over 300,000 soldiers, a number which probably does not include many of the troops of Antony and Lepidus, whose services he did not require. The most important years in this respect were 30 and 14 b.c. In the latter year many of the soldiers whom he had retained after Actium had completed their period of service, and it was probably about this time that the principles which were to guide him were definitely accepted.

In deciding how many legions were to be retained in the army Augustus was guided by considerations both of policy and of finance. He must have been well aware that the contemplated extension of the Empire to the Elbe and the Danube could not be accomplished without much fighting. On the other hand he had decided in 20 b.c., when he recovered the standards captured at Carrhae, to abandon the aggressive policy of Caesar and Antony in the East, and to aim at establishing friendly relations with the Parthians. About the same time, as he says himself, he could have made Armenia a province, but preferred to entrust it to a king who recognized the suzerainty of Rome. Thus only in the North was it likely that actual fighting would occur. The long wars in Spain had come to an end in 19 b.c., and the campaigns in Africa and Arabia were not likely to be repeated. A decision was also very desirable from a financial point of view. Augustus had devoted years to the task of reorganizing the taxation of the Empire, and it was essential for him to know what he would have in the future to spend on the army, by far the most important item of expenditure in the Roman budget. Accordingly in 13 b.c. he reached a final decision about the number of the legions and the conditions of legionary service.

The discovery of a papyrus showing that a legion numbered XXII existed in 8 b.c. has definitely disproved the view of Mommsen that Augustus after Actium reduced the army to eighteen legions and raised many more in the troubled years a.d. 6—9. It is now generally agreed that from 14 or 13 b.c., if not earlier, the army contained twenty-eight legions, three of which were lost with Varus in a.d. 9, and not immediately replaced. Thus under Tiberius there were twenty-five legions. Two were added by Claudius (XV and XXII Primigenia) and by the time of the accession of Vespasian there were three more (I and II Adiutrix and I Italica). The foresight of Augustus is established by the fact that Trajan, the best soldier among his successors, was content with an army of thirty legions.

Although the principle that frontier defence was to be the main function of the legions goes back to Augustus, so many wars occurred during his reign that they were moved from province to province to a greater extent than was customary under his successors. The historian, Velleius Paterculus, who was attached as military tribune to a legion (probably V Macedonica) whose headquarters were in Macedonia, saw service in the eastern provinces. During the Pannonian revolt legionary reinforcements were brought from Macedonia and Syria. It is thus difficult to state with any accuracy the normal distribution of the legions at this period. But from the accession of Tiberius the task is easier. In a.d. 23 there were three legions in Spain, eight on the Rhine, seven in the Danubian provinces, four in Syria, two in Egypt, and one in Africa. This remained the normal distribution during the Julio-Claudian period, though the conquest of Britain under Claudius and Corbulo’s operations in the East involved certain modifications. After the Flavian period only one legion is found in Spain, and none at all in Dalmatia. The majority of the pro­vinces were unarmed, and the military forces were concentrated on the frontiers.

The wisdom of this military system cannot be discussed apart from the general problem of the frontier policy of the Principate. Here it must be enough to say that the absence of any reserve units which could have been sent as reinforcements to threatened points on the frontier might well have had grave consequences. In order to strengthen any one part of the long frontier it was necessary to weaken another, so that if the Empire had been attacked simultaneously on two or more fronts it might well have collapsed. Fortunately this situation was unlikely to arise. The tribes beyond the Rhine and the Danube were too disunited to be a serious danger, and by indirect means Rome fostered their natural tendency to disunion. In the East an unaggressive policy was pursued. No serious attempt was made to annex Armenia before Trajan, and few kings of Parthia were strong enough to con­template any extension of their kingdom at the expense of Rome.

A more serious objection to the system is one which becomes obvious in the year of chaos which followed the death of Nero, during which the armies of the Rhine, the Danube, and the Euphrates supported different candidates for the throne. Nothing did more to secure the support of the eastern legions for Vespasian than the rumour that his rival had proposed to move them to the Rhine. The ties which bound groups of legions to each other and to the provinces in which they were stationed were inconveniently close: the soldiers, whatever their origin, tended to regard these provinces as their home. But this development of esprit de corps in the separate armies was likely to cause trouble only when the throne was vacant for all armies were usually loyal to the emperor for the time being. At the same time it cannot be said that in this period the army was a unit that was normally conscious of its power or disposed to use it, or that the emperor was master of the State by virtue of being the representative of the soldiers and their interests.

The connection between the magistracy and military commands long outlasted the Republic, and the higher officers of the legions of the early Principate can hardly be described as professional soldiers. Though no magistrate performed military duties during his year of office, the commanders both of provincial armies and of individual legions were (except in Egypt) men who had reached a fairly definite stage in the senatorial cursus honorum. Each legion was commanded by a legatus, who was at first an ex-quaestor and later almost invariably an ex-praetor. This office was a creation of Augustus, though he had to some extent been anticipated by Caesar, who put sections of his army under carefully selected legati. The post must have given its holder valuable experience, but no man held it long enough to establish close ties between himself and his soldiers. After a year or two he returned to Rome to hold another magistracy or was transferred to one of the numerous provincial governorships held by men of praetorian rank. The only opportunity of gaining military experience open to a man who hoped to command a legion was in the office of tribunus militum, which in the Principate, as in the later Republic, was held by young men who had not yet entered the Senate and were considered to be members of the equestrian order. The duties of these tribuni cannot have involved much responsibility, and they must have been regarded primarily as learners. Rome possessed no military colleges, so that the future governor of Britain or Pannonia was expected to acquire military knowledge by practical experience alone. Agricola’s military experience before his governorship of Britain consisted of about a year as military tribune followed after a long interval by perhaps three years as legatus of a legion: yet his son-in-law describes him at this stage of his career as a vir militaris. If the foreign policy of Rome had not been so unaggressive, the system just described might have had serious results. Usually the governor even of an important frontier province was not an experienced soldier. At a critical moment a special appointment had to be made: the position of Corbulo in the East during Nero’s reign recalls the extraordinary commands of the Republic. There is at least some truth in the suggestion of Tacitus that the emperors were unwilling that senators should have opportunities of gaining military distinction.

The absence of professional experience among the higher officers was to some extent remedied by the institution of the centurionate. Each legion had sixty centurions, six attached to each of its ten cohorts. The senior centurion was called primus pilus, and it was customary for the commander to consult a group of centurions known as the primi ordines, which consisted probably of all the centurions of the first cohort and the senior centurion of each of the others. Many, perhaps most, of the centurions had risen from the ranks, but quite early in the Principate it was possible for men belonging to a higher social class than most of the private soldiers, and even for equites, to begin their military career as centurions. Such men were promoted rapidly and were transferred from legion to legion and from province to province, while their colleagues who had started in the ranks sometimes spent the whole of their military life in the same legion. All centurions however had an experience which must have been of great value to their nominal chiefs. On retirement a primus pilus had good prospects of interesting work. He might as an eques become tribune of a praetorian or urban cohort in the city of Rome, or receive a command in Egypt or in the auxiliary forces, or even in the early Principate become tribune of a legion. Many financial posts were open to him. Finally, he might settle in a town and hold municipal office. He normally received equestrian rank, and might well have sons who entered on the senatorial career.

On the whole then the legionary officers had much less professional experience than the rank and file. The tribuni and legati were almost amateur soldiers, and even among the centurions there were many who regarded their military service mainly as a preparation for a civilian career.

If in the early Principate the great majority of the soldiers, at least in the western legions, were men of Italian birth, the reason was that comparatively few of the provincials possessed the Roman franchise. With the extension of the franchise by colonization and other means the provinces came to provide a very considerable proportion of the legionaries, and from the Flavian period onwards the number of Italians in the legion steadily declines. From the beginning the eastern legions were mainly recruited in the eastern provinces, especially in Galatia, and the soldiers must often have been given citizenship on enlistment. Of 61 soldiers serving in the Egyptian legions in the first century 53 are known to have been natives of Asia Minor, Syria, and Egypt. The division of the Empire into the Greek-speaking East and the Latin-speaking West is reflected in the army. The western legions were recruited in Italy and in such romanized provinces as Baetica and Gallia Narbonensis. The Danubian army drew on both eastern and western provinces, while, as has been said, the eastern legions were almost entirely eastern in their composition.

It is probable that the conditions of service established by Augustus in a.d. 5-6 were not in the first instance strictly observed. One of the main grievances of the mutinous legionaries at the beginning of the reign of Tiberius was that they were retained with the colours sometimes for thirty or forty years, and that even after formal discharge military duties were imposed on them. The Emperor was forced to make concessions which had almost immediately to be cancelled for financial reasons. Twenty years remained under the Julio-Claudian emperors the normal period of legionary service. Even in a.d. 23 the situation was not satisfactory. In that year Tiberius thought of visiting the provinces in order to raise new troops in place of the veterans who were clamouring for discharge. The cause of the trouble was probably financial. It took time before the aerarium militare established in a.d. 6 would contain sufficient funds to provide adequately for old soldiers, and in the interim it was simplest to retain them in the legions. The policy of settling veterans in colonies was not abandoned when in a.d. 5 the scale of gratuities was fixed. Colchester and Cologne are only two examples of the military colonies of the Julio-Claudian age. Sometimes old soldiers were expected to settle in Italian towns, but it seems that this policy was unpopular. Men settled by Nero in Tarentum and Antium drifted back to the provinces where they had served. It has already been noted that soldiers formed close ties with the inhabitants of the districts in which their legions were stationed. When the Germans in a.d. 70 urged the people of Cologne to kill all the Romans in their city the answer was: ‘Soldiers who have been settled here and are united to us by marriage and the offspring of these unions regard this town as their home: you cannot be so unreasonable as to wish us to kill our fathers, our brothers, and our children’. Legal marriage between a soldier and a provincial woman was not permitted during active service. The laws enforcing matrimony did not apply to soldiers. There were no married quarters in legionary camps. But the immobility of the legions led to the formation of alliances which were often legalized when the soldier got his discharge.

The life of a Roman legionary must often have been an unexciting one. He was usually attached for twenty years to the same legion, cohort, and century, and might well spend all his military life in the same camp. Important campaigns were so rare that a man might get his discharge without ever having fought in a battle. When Corbulo went to the East in a.d. 58 he found that discipline had become very slack. ‘The soldiers, demoralized by a long peace, endured impatiently the duties of a camp. The army contained veterans who had never acted as sentry or guard, to whom the rampart and ditch were new and strange sights, men without helmets and breastplates, sleek money-making fellows who had served all their time in towns’. Sometimes generals employed their idle troops on useful work. Under Claudius the Rhine army, much against its will, was forced to dig for silver in the Taunus district, and a little later an enter­prising commander proposed to construct with military labour a canal from the Moselle to the Saône which would have enabled ships to sail from the North Sea to the Mediterranean. A certain proportion of the private soldiers might hope to reach the rank of centurion, and for others there were specialist jobs in the orderly-room or in the camp-hospital: some were despatch-riders and others horn-blowers. It was a great honour to bear the signum of a cohort or the aquila of the legion. Sometimes a soldier would have an opportunity of visiting another province through being seconded to a detachment sent to assist a governor whose army required temporary reinforcement.

III. THE AUXILIA

If the army of the Principate had consisted of legions alone it would have been too small to perform its functions. At full strength the twenty-five legions which existed at the death of Augustus contained only some 150,000 men. Accordingly, a second force of about the same size was raised from among the provincials, and organized on a different system. As was stated above the armies of the Civil War and the Triumvirate consisted not only of legions but of smaller units of both infantry and cavalry, recruited in the provinces and frequently commanded by their own chiefs. For instance, when Antony crossed the Euphrates in 36 b.c. he was accompanied by some 10,000 Gallic and Spanish cavalry, some of whom took part in his final campaign against Octavian.

Thus after the battle of Actium Augustus was called upon to decide, not merely how many legions should be retained, but whether any, and, if so, how many of these irregular units should be given a permanent place in the army. What was his exact decision it is difficult to say, but it is certain that during his reign a very considerable number of auxiliary units existed. No less than 70 cohortes of infantry and 14 alae of cavalry helped to crush the Pannonian revolt: these constituted a force of about 50,000 men, and it is possible that the total number of auxiliaries under arms at this time did not fall far short of 150,000, and was roughly equivalent to the number of the legionaries. Whether many of these units had existed before Actium is doubtful, but the names borne by certain cavalry squadrons suggest that they had originally been raised in Gaul by Caesar’s officers.

Without the creation of such a force full use could not have been made of the resources of the provinces in military material, for it was impossible to break suddenly with the tradition that Roman citizenship was a necessary qualification for service in the legions. Under the Republic few provincials possessed the citizenship, and even under Augustus there were many parts of the Empire where it was rare, but whose inhabitants were well fitted to be soldiers. It was in these regions that the great majority of the auxiliaries were recruited. With a very few exceptions only the imperial provinces were drawn upon, while the Romanized inhabitants of the senatorial provinces served in the legions.

The districts in which auxiliary units were originally recruited can usually be told from their titles e.g. Ala I Tungrorum, Cohors II Raetorum, Cohors I Thracum, but it is a mistake to suppose that the bodies of troops which bore such titles always retained their local character. In some districts the territorial system of recruiting was soon abandoned and at least as early as the reign of Tiberius recruits were accepted from among the inhabitants of the provinces in which the units happened to be stationed. It has been said that ‘the nominal rolls of many cohorts formed under Augustus must a century later have represented a map of the regions in which they had at one time or another served’. Undoubtedly Pannonians are found in ‘Spanish’ cohortes and Ger­mans in ‘African’ alae quite early in the Principate. In this way something was done to discourage purely local patriotism, to foster a common allegiance to Rome, and to spread the use of the Latin language, which must have been necessary as a means of communication between the heterogeneous elements included in the auxilia.

But this point must not be exaggerated. There is no doubt that till the end of the Julio-Claudian period a very large proportion of these units retained their national character and were stationed not far from their homes. This is particularly true of the Rhine frontier, where troops of Gallic nationality were employed at any rate till the rising of a.d. 69-70. It is clear from Tacitus’ account of this rising that the titles borne by these units can safely be used to determine their composition. The Batavian cohorts, for example, which are so frequently mentioned, were evidently homogeneous, and this is true of most of the other bodies of auxilia which bear Gallic or German names. That there was at this time strong feeling against service far from home is shown by what happened in Thrace under Tiberius. Thracians who were quite prepared to serve under their own leaders against neighbouring tribes, were infuriated when it was reported that they might be ‘separated from each other, attached to other peoples and dragged away to distant lands’. A little later we find the same situation in Britain. British troops were willing to serve loyally under Agricola against the Caledonian tribes, but regarded it as a grievance to be called upon to serve elsewhere than in Britain. Accordingly it is not surprising that three-quarters of the Rhenish auxilia in 69 were drawn from Gaul proper or the Teutonic tribes of the Belgic province. It was probably in the Danubian provinces that the practice of the local recruiting of auxilia was first adopted. After the Pannonian Revolt, which demonstrated the danger of training what might be a national army in a province, many of the local auxiliary units seem to have been sent elsewhere and their place taken by troops from other provinces of the West, especially from Spain. But when new recruits were wanted for these Spanish units they were not always brought from home, and suitable applicants were accepted from the districts in which they were stationed.

The auxiliary forces of the Roman army were organized in cohorts of infantry and alae of cavalry. In the first century both cohorts and alae were normally composed of about 500 men, though units of 1000 occur, and later become common. The infantry commander was called praefectus cohortis, and the cavalry commander praefectus equitum and later praefectus alae. During the greater part of the Principate these posts together with that of tribunus militum in the legions constituted the so-called militia equestris, and were held by young men who aspired to a career in the equestrian cursus honorum. Though an eques could never command legions (except in Egypt), the military experience gained in his youth as commander of a cohors and ala would stand him in good stead if he later became procurator of such a province as Mauretania or Thrace, which contained a considerable force of auxiliaries.

But at the beginning of the Principate the time had not come to entrust these commands to young men without military experience. Accordingly the earliest praefecti were taken mainly from two other sources, legionary primi pili, whose previous training must have qualified them admirably to keep order in a force raised in the less civilized parts of the Empire, and tribal chiefs. So long as the cohortes and alae consisted almost entirely of men belonging to one tribe or drawn from one district it was often thought best to put at their head a man of their own race who had been granted the Roman citizenship, but who did not intend to enter on the normal cursus honorum. The leaders of the revolt on the Rhine in a.d. 69 were praefecti of this type, and the experience gained by the African chief Tacfarinas as an officer of auxilia rendered him a dangerous opponent of Rome in the reign of Tiberius. From the Flavian period auxilia are not commanded by tribal chiefs, and the development of local recruiting rapidly deprived the units of their territorial character. Even in the Julio-Claudian period isolated examples occur of young praefecti of the later type, and the militia equestris seems to have been organized by Claudius. But before the reign of Vespasian the majority of the praefecti were probably derived from other sources.

The subordinate officers of the auxilia, the decuriones of cavalry turmae and the centurions of the cohorts were Roman citizens who were frequently promoted to the legionary centurionate. The private soldier seems to have had little prospect of promotion.

Most of our information about the auxilia is derived from the certificates of discharge, the so-called diplomata militaria, which were granted to a soldier on the completion of twenty-five years of service, and which record the gift of citizenship and the legalization of any marriage which he had contracted or might hereafter contract. It has been questioned whether this privilege goes back to Augustus, who granted the citizenship sparingly, but it is certain that by the middle of the first century a.d. every ex-soldier of the auxilia was a Roman citizen. By this time the rates of pay and of retiring-allowances were no doubt fixed, but we have no detailed knowledge of the subject. This generous policy must have done much to promote the provincialization of the legions, for one cannot doubt that many sons of these enfranchised auxiliaries enlisted in them. In two or three generations the descendant of an inhabitant of a backward province might reach the highest posts in the senatorial career.

As the regularly constituted cohortes and alae could not absorb all the provincials who were qualified for military service, many others were at critical periods enrolled by Roman generals under officers who were usually termed praefecti levis armaturae. In his invasion of Germany Germanicus made use of these tumultuariae catervae, and so did Corbulo in his eastern wars. They are frequently mentioned in the Histories of Tacitus and are found in Raetia, Noricum, the Maritime Alps and in Mauretania. In Switzerland the garrisoning of at least one fort was entrusted to troops of this kind. They were distinguished from the regular auxilia by being liable to service only in their own districts. It is probable that they were disbanded at the end of a war.

Finally, it must be mentioned that Rome made demands for military assistance on such client-kings as were allowed to survive. Before the organization of the province of Moesia the defence of the lower Danube was probably entrusted to the kings of Thrace, one of whom gave valuable assistance in crushing the Pannonian revolt. This kingdom became a province under Claudius, but farther east several kingdoms survived whose rulers were called upon for assistance by Corbulo and offered their services to Vespasian when he decided to aim at the throne.

IV. THE GARRISON OF ROME

In other chapters mention is made of the important part played by the Praetorian Guard and its commanders in the history of this period, especially at times when the throne was vacant. This famous body of troops, which consisted of nine cohorts, each containing 1000 men, was in theory the bodyguard of the princeps. It performed in Italy the duty of preserving law and order which in the provinces belonged to the legionary and auxiliary forces. Holders of imperium under the Republic had been attended by a body of picked soldiers, drawn perhaps mainly from young men of the upper classes, who in this way satisfied the legal requirements of military service, but the resemblance of the Praetorian Guard of the Principate to such units was merely one of name. Under Augustus only three of the cohorts were stationed in Rome itself, the remaining six being quartered in various towns of Italy—three were for a time as far from the capital as Aquileia—but Tiberius concentrated all nine in a camp outside the north­east gate of the city. As the personal bodyguard of the emperor the praetorians were not liable to active service except when he or some member of his family took the field, and as this rarely happened under the Julio-Claudian dynasty, it is not surprising that they were regarded with envy and perhaps a little contempt by the legionaries, whose conditions were less comfortable, whose period of service was longer, and who received less than a third of their pay.

The rank and file of the praetorians was in the early Principate recruited mainly from Central Italy, while the Italians who served in the legions were drawn to a large extent from Cisalpine Gaul. But some exceptions occur. We happen to know that members of certain Alpine tribes of the Trentino, whose very claim to the citizenship was doubtful, had reached the rank of centurion in the Guard under Claudius, and more than one praetorian of this period was a native of Macedonia or even of Asia Minor. Though, as will be seen, the commanders of the praetorian cohorts had usually served with the legions, private legionaries could seldom hope to be transferred to Rome. The example set by Vitellius of enrolling legionaries in the Guard was not followed till the end of the Second Century. The majority of the praetorians were infantry, but to each cohort a squadron of cavalry was attached.

The praefects of the Guard were normally two in number, but the office was held without a colleague by Sejanus during the greater part of the reign of Tiberius, and by Burrus from 51 to 62. The praefect was with rare exceptions a man of equestrian rank, and was often of very humble origin. Nymphidius Sabinus who aimed at the throne on the death of Nero was the son of a freed­woman, and the parentage of Tigellinus was obscure. Plotius Firmus, praefect under Otho, had served as a private soldier. It is probable that Burrus was not an Italian but a native of Narbonese Gaul. The important position gained by these men illustrates the fact that under the Principate the possession of high birth was by no means essential for success in public life.

The separate cohorts were under the command of tribune, who had usually held the primipilate of a legion and had thereafter acquired equestrian rank. A tribunate in the praetorians or the other city-troops was a regular stage in the equestrian cursus honorum and often led to important procuratorships and praefectures.

The life of a praetorian of the Julio-Claudian period can hardly have been a very strenuous one, and the routine nature of his duties must have made it hard for him to distinguish himself. The inscription which records the career of a man who accompanied Claudius to Britain as a private of the Guard, and subsequently gained equestrian rank and the procuratorship of Lusitania is almost unique. As a rule such a man could not aspire to more than a centurionate in his cohort or to admission to the body of 300 speculators who formed within the Guard a corps d'elite. But the conditions of service were good. He served for only sixteen years, was paid two denarii (32 asses) a day, and on discharge was given a gratuity of 5000 denarii. The legionary served twenty years or more, was paid ten asses a day, and his gratuity amounted to no more than 3000 denarii.

It is a mistake to regard the praetorians as the city-police of Rome. This duty belonged to a separate group of cohortes urbanae, three and later four in number, under the command of the praefectus urbi a senator of consular rank whose duty it was to keep order in the city. Individual cohorts were commanded by tribuni, men of the same type as the tribuni of the praetorians. The urban cohorts were not exempt from regular military service—they were employed by Otho in his war against the Vitellians—but on the whole they were confined to the city to an even greater extent than the praetorians. The cohorts which garrisoned the important provincial cities of Lugdunum and Carthage were reckoned as belonging to the urban cohorts. The pay was lower than that of the praetorians, and the period of service lasted twenty years. Whatever may have been the case under the Re­public, the force employed by the Principate to maintain law and order in the city cannot be described as inadequate.

In addition to the praetorian and urban cohorts there were created in a.d. 6 seven cohortes vigilum under a praefectus vigilum, whose primary duty was to act as a fire-brigade. In 21 b.c. this task had been assigned to an aedile with the assistance of 600 public slaves, but it was later decided that the work could be better performed by an equestrian nominee of the Emperor at the head of 7000 men. Each cohort was responsible for the safety of two of the fourteen regions into which Rome was divided. A peculiar feature of these units was that membership was open to freedmen, who were rigidly excluded from most departments of the army: a law of a.d. 24 conferred after six years of service the full citizenship on any of the vigiles who had not acquired it at the time of their manumission. The praefect of the vigiles was second only to the praefect of the praetorians among the equestrian officials of Rome, and frequently succeeded to his office. The tribuni vigilum later on usually held a similar post in the urban and praetorian cohorts.

Finally, mention must be made of the so-called German bodyguard which from the time of Augustus to that of Galba was closely attached to the persons of the emperor and of members of his family. It was recruited from tribes on the very fringe of the Roman Empire such as the Frisii, the Ubii and especially the Batavi. Its members were not citizens, but adopted such Greco-Roman names as Felix, Phoebus, Nereus, and Linus. In the reign of Nero a special burial-ground was allotted to them from which some stones survive. About the same time they were organized in a collegium under a curator Germanorum.

V. THE FLEET

The statement that ‘every true Roman was afraid of the sea’ contains this amount of truth that except at great crises the government of the Republic failed to realize the importance of sea­power. The successful termination of wars was postponed by the need of creating fleets, and little appreciation was shown of the fact that in the absence of a permanent navy seafarers in the Mediterranean were certain to be exposed to danger from pirates. If the Roman government of this period had, as has sometimes been assumed, been influenced by a desire to encourage commerce, it could hardly have failed to do more than it did to produce the conditions which make commerce possible. Naval service ranked lower than service in the legions, and the hastily improvised fleets consisted mainly of ships contributed by maritime cities in the provinces. No class of naval officers was created, so that when it was decided to take vigorous measures against the pirates, it was to a great soldier that the task was entrusted. Even Caesar does not seem to have realized fully the need of possessing a navy comparable in efficiency to his legionary forces.

But Augustus had learned valuable lessons in his wars against Sextus Pompeius and Antony, and the influence of Agrippa, the victor of Naulochus, must have been exercised in favour of the policy of retaining part at least of the fleets which had fought at Actium. It is very much to the credit of Augustus that, in spite of the decisive character of his victory, he did not follow the example of Republican generals in disbanding the fleet which had helped to secure it.

Early in his reign he organized the two Italian naval bases which were destined to remain for centuries the headquarters of the principal Roman fleets, Misenum on the Bay of Naples, and Ravenna; near the mouth of the Po, with which it was connected by a canal. A squadron consisting of ships captured at Actium was for some time stationed at Forum Julii in Gallia Narbonensis, and probably all provincial governors had some warships at their disposal; we happen to hear of liburnicae in Corsica in a.d. 69. Regular fleets are found early in the Principate at Alexandria, at Seleuceia the port of Antioch, in the Black Sea, and on the Rhine and Danube. The Rhine fleet played a prominent part in the operations in Germany conducted by Drusus and later by his son Germanicus, who in a.d. 16 had a thousand ships of one kind or another under his command. Communications between Britain and the mainland were maintained by a fleet which is mentioned in a.d. 70 and was used by Agricola in his campaign against the Caledonians.

The reign of Claudius probably marks an important stage in the organization of the fleet. Previously it seems to have been regarded as belonging less to the armed forces of the State than to the household of the princeps. In the war against Sextus Pompeius slaves had been freely employed as oarsmen by both sides, and the practice was continued by Augustus. Early inscriptions prove that even the trierarchs who commanded ships were slaves or freedmen of the emperor, and it cannot be doubted that the majority of the oarsmen at this period were slaves. But by the time of Claudius we find free provincials among the sailors, and at the end of the reign of Nero the servile element must have disappeared. For in a.d. 68-70 two whole legions I and II Adiutrix—were created out of men serving in the Italian fleets. Inscriptions show that the soldiers of these legions were mainly natives of Dalmatia, Pannonia, and Thrace. Tacitus emphasizes the fact that the support given to Vespasian by the fleet at Ravenna was due to the adherence of the Danubian provinces to his cause. It is hardly likely that even during the civil wars slaves or freedmen would have been enrolled as legionaries. From the time of Claudius the fleet was evidently regarded as a part of the regular auxilia. Sailors received citizenship on discharge after twenty-six years of service, and their children would be able to serve in the legions.

Even under the Principate little seems to have been done to create a class of professional naval officers. In the Julio-Claudian period the praefecti who commanded fleets were either freedmen of the emperor like Anicetus who was in charge of the ships at Misenum when Agrippina was murdered, or ex-legionary primi pili of equestrian rank. Moschus, the commander of Otho’s fleet, was probably the last freedman to hold this post, but the fact that in 79 the fleet at Misenum was commanded by a scholar like the elder Pliny suggests that the standard of seamanship was not a high one. Lucilius Bassus, to whom both the Italian fleets were entrusted by Vitellius, had commanded a squadron of cavalry, and hoped to be praefect of the praetorians.

Regular sea battles rarely occurred under the Principate, and the so-called ‘soldiers’ of the fleets must be regarded primarily as oarsmen: if actual fighting was expected it is probable that legionaries were taken on board. The fleets were normally employed on such duties as conducting governors to their provinces, bringing prisoners to Rome, and escorting transports and corn­vessels. Under Claudius sailors were employed in organizing a ‘sea-fight’ on the Fucine Lake, and later on so many of them were brought to Rome on various duties that special barracks were erected for them. As the work required of the navy called primarily for speed it is not surprising that it consisted mainly of light liburnicae with only two banks of oars, the value of which even in battle had been demonstrated at Actium. In a world dominated by the pax Romana there was no need for the huge warships of the Hellenistic age.

No aspect of the work of Augustus and his successors is more worthy of careful study than their organization of the defence of the Empire. The army and navy were potent instruments of Romanization. Though the troops often complained of the conditions of service and the provincials of the taxation rendered necessary by the need of defending the frontiers, such complaints became rarer with the lapse of time. The attempt of Gaul to throw off the Roman yoke in a.d. 69—70 was a half­hearted affair. As has been shown, the task of defending the Empire was entrusted to an increasing extent to the provincials themselves, who found in army service a means of acquiring the citizenship and often of rising to high positions in the service of the government. If Rome seems to have taken unnecessary risks in attempting to defend her long frontier with an army of some 300,000 men, it must not be forgotten that the size of an army is determined by policy, that Rome seldom aimed at territorial aggrandisement, and that her diplomacy was usually successful in preventing the consolidation outside the Empire of a power strong enough to threaten its security.

CHAPTER IX

THE EASTERN FRONTIER UNDER AUGUSTUS