The comitatenses had an entirely separate command structure and were more likely to be moved from one region to another. The name was derived from comitatus (the imperial household), and the original idea was clearly that they should be at the emperor's disposal. It is possible that under Constantine they were organised as a single army, ready to follow on campaign wherever he went. When his three sons divided up the empire in 337, the comitatenses were divided into three separate armies. Over time, more distinct armies stationed in specific regions would be created. In practice, the comitatenses were usually commanded by generals with the title `Master of Soldiers' (MagisterMilitum), such as Silvanus and Ursicinus. Variants of the title included `Master of Horse' (Magister Equitum) and `Master of Infantry' (Magister Peditum), neither of which commanded exclusively infantry or cavalry, but a mixture of both. As subordinates, the Masters of Soldiers had officers with the rank of comes (count, pl. comites). Again, the word had its root in the personal companions who had traditionally accompanied an emperor on a journey or campaign. In some cases counts were given small-scale independent commands.4
The Masters of Soldiers regularly commanded substantial numbers of troops, although it is unlikely that these forces were bigger than the army controlled by a senatorial legate in a major military province in the first or second century. There were only three of them - the number would double by the end of the century, but never increase beyond that - and this made it easier for the emperor to keep a close watch on them. Yet the Silvanus episode had shown that this might not be enough. More important in ensuring the emperor's security were the complex divisions of responsibility and power throughout the provinces. The army was divided into two, with comfortably over half of its units being limitanei. However, co-operation between limitanei and cornitatenses does appear to have been common, and senior officers could in practice find themselves with troops of both types under their command during a campaign. A much bigger division was maintained between the army hierarchy and the civil administration.
The army depended on the civilian bureaucracies to supply it with pay, food and clothing. Even weapons and other equipment, which in the early empire had been made in the legions' own massive workshops, were now provided by state-run arms factories under the supervision of the praetorian prefects. A Master of Soldiers planning to challenge the emperor had to secure not just the support of his soldiers, but the cooperation or replacement of large numbers of bureaucrats. It was much harder for one man to know, and win over, everyone who was important. At the same time, there were many people serving in independent hierarchies able to send real or fabricated reports of the disloyal behaviour of others. The system offered some protection to the emperor, at the cost of making it more difficult to get things done. Campaigns could be delayed or hindered by lack of supplies over which the commanders had no control.'
The Roman army in the fourth century was large, its manpower still dwarfing that of the swollen bureaucracy. The vast majority of the men paid and under the control of the emperors were soldiers. Yet we do not know how big the army was. Most scholars assume that it was larger than the second-century army, perhaps 50 per cent or even ioo per cent bigger, but the evidence is inadequate and inevitably the calculations involve a good deal of conjecture. We do know that the fourth-century army contained many more units and we have a complete list of those in existence at the very end of the fourth and the beginning of the fifth century. Some units had disappeared since Constantius II's time, others had been created, but this list gives us a fair idea of the overall shape of the army in his day. Unfortunately, we have no certain evidence for the size of each unit so cannot calculate the army's theoretical total size from this.6
The limitanei included a very broad range of unit types. Some were survivals from the time of Marcus Aurelius and even earlier. There were legions, as well as auxiliary cohorts and cavalry alae. Others were new creations. Overall, there was a higher proportion of cavalry units in the limitanei than in the comitatenses, no doubt because they were useful for patrolling. There were no units including both infantry and cavalry, equivalent to the mixed cohorts of the early empire. Legions were sometimes stationed in several outposts. Several were split amongst five garrisons, while in the early fifth century the Legio XIII Gemina provided five garrisons on the Danube, another in Egypt and also had a unit amongst the comitatenses. Even so, they were certainly far smaller than the 5,ooo-man legions of the early empire. It is also more than possible that most units were smaller than the roughly Soo-man cohorts and alae of the auxiliaries in the second century. Very many of the forts occupied by the limitanei were tiny, most a small fraction of the size of earlier auxiliary forts. An Egyptian papryus dating to the start of 30o also suggests some very small units. It mentions a cavalry ala with ii6 - just over a year later this had risen to ii8 - a vexillatio of legionary cavalry with 77 men and a unit of mounted archers with 121. A number of units of legionary infantry averaged around the 500 mark, but a camel troop seems to have had just a couple of dozen men.7
The situation with the cornitatenses is no clearer, although there was less variety of unit types. Infantry consisted of legions and a new type of unit known as auxilia. All of the latter and some of the former were rated as palatina, a title that carried much prestige and some tangible advantages in pay and bonuses, but no difference in function. Cavalry units were all called vexillationes and were smaller than the infantry regiments. A common estimate is to give cavalry units a strength of boo and the infantry somewhere between I,ooo and 1,200. However, the few mentions of regimental strengths in our sources suggest smaller numbers, averaging around 350-40o and Boo respectively. What we do not know is whether such lower figures represent actual campaign strengths, reduced by disease and casualties, or theoretical sizes. A couple of sources mention commanders who kept non-existent men on their unit's role so that they could draw their pay and rations. Infantry units of colnitatenses were brigaded in pairs, and seem to have permanently operated together. This obviously adds an extra complication since we cannot be sure whether numbers in our sources refer to a single regiment or a pair that the author naturally assumed would be together!
Overall, it is fair to say that the units of the fourth-century army were smaller than their first- and second-century predecessors. Going much further than this quickly becomes conjectural. We cannot even be sure that all units of a particular type had the same theoretical size. Infantry regiments of all types in the field army were probably somewhere between 500 and i,ooo men strong, cavalry units about half the size of infantry. Many units of limitanei may have been a good deal smaller, and perhaps we should think in terms of 50 to 200 men, which would make them more like companies than battalions by modern standards. It is possible that on paper the total strength of the army was larger than in Marcus Aurelius' day, but we cannot be sure of this. Its actual strength on a dayto-day basis is even harder to assess.'
The evidence is equally poor for the army's recruitment. Some men were volunteers and others conscripts, but the balance between the two is unknown. Sons of soldiers were legally obliged to join the army. Landowners had to supply a set number of recruits as part of the taxation system, but were often able to commute this duty to a money payment or avoid it altogether. There was also a steady supply of drafts for the army from the groups of barbarians settled by treaty within the empire and obliged to provide soldiers for the army. Tribesmen from outside the empire also came as individuals or as groups to enlist in the army. The old idea that this influx of Germans `barbarised' the Roman army and over time reduced its efficiency has been discredited. There seems to have been no real difference in reliability and performance between recruits from inside or outside the empire. As we have seen in the last chapter, the senior ranks included many men of barbarian descent who behaved exactly like colleagues of more traditionally Roman stock.
The army took recruits wherever it could get them, and there are clear signs that many people went to drastic lengths to avo
id service. In real terms army pay was of less value than it had been in the first and second centuries, while discipline and punishment remained brutal. Repeated laws punished the practice of self-mutilation to avoid being conscripted - potential recruits cut off their thumbs so that they would be unable to hold a sword or shield properly. There was a famous case of an equestrian who had done this to his sons during Augustus' reign, so the practice was not new, but it does seem to have become more common. The frequency of legislation dealing with the problem suggests that the laws were not effective. A letter from a clergyman to a garrison commander in Egypt asked that he exempt a widow's son from conscription or, failing that, at least enlist him in the local limitanei so that he could stay near home instead of sending him away to join the comitatenses. The fourthcentury army did not have massive resources of manpower and this factor played a significant part in shaping its operations.'°
Whatever the actual size of the fourth-century army, more units certainly meant more officers to command them. Regimental commanders were usually called tribunes, although other titles such as praepositus were also used. Such a post gave a man considerable status - even if, once again, his pay and social importance were somewhat less than those of an equestrian officer in the second century. In comparison to the early Principate, the Late Roman army was top heavy in its command structure. It is more than likely that the desire to reward supporters with high rank - and in some cases their own independent commands - had as much to do with the multiplication of units as any practical concerns. We hear of unattached tribunes, sometimes serving in a staff capacity, and it is more than likely that there were significantly more men with commissions than there were units for them to command. Some tribunes may well have been promoted after service in the ranks. A much more common route was to be commissioned from special units at the imperial court. The candidati (candidates) acted as personal bodyguards of the emperor during court ceremony. The protectores domesticiserved as junior staff officers either with the emperor or a Master of Soldiers. Ammianus was one of these. Promotion was officially the emperors' prerogative, but in practice he had to rely on recommendations of senior officers, officials and courtiers. There was no formal system for training these officers or for selecting on the basis of talent. As always in Roman society, patronage played an important role in determining a man's career."
Modern scholars conventionally refer to the comitatenses as mobile field armies, and often they go further and dub them elite troops. They are seen as a necessary response to the greater external threats facing the empire. In the past, wars requiring the removal of troops from one frontier zone weakened defences there and left the region vulnerable to attack. In the fourth century the limitanei remained permanently in place. They were not as numerous as the forces on the frontiers in the early empire and could not hope to defeat major incursions. Yet their bases were strongly fortified, as were towns and cities, and they were expected to hold out for as long as they could and harass the enemy. A sizeable army of comitatenses could then be sent to the region to confront the invader. In essence, they formed the mobile reserves that it is claimed the earlier deployment lacked."
Much of this analysis has been called into question, particularly the sense in which they acted as reserves. Nothing of this sort is ever implied by the ancient sources. No army could ever move faster than an infantryman could march, and more often than not its speed was reduced to that of the plodding draught oxen that pulled its baggage train and carried its food supply. Given the size of the empire, talk of reserves makes little sense, since unless they were fairly close to the theatre of operations then it would take them a very long time to get there. In spite of such criticism, the `mobile field army' tag has stuck, so that it is worth making a few points about the actual deployment and use of the cornitatenses.
Unlike the lilnitanei, the colnitatenses did not occupy permanent garrison posts. When not on campaign they were stationed within the provinces and not on the frontiers. However, they were not kept concentrated as large army corps ready to take the field at a moment's notice, since this would have made it difficult to supply them. Temporary camps, the men living in tents or roughly built shacks, were unhealthy in winter, and in any case it was dangerous politically to keep armies concentrated during the winter months of inactivity in case they rebelled. The army did not build large bases in this period, and even many of the existing legionary fortresses designed to accommodate 5,ooo men in the second century were now abandoned or substantially run down. At the beginning of the sixth century the historian Zosimus claimed that Diocletian had kept the empire secure by stationing the whole army along the frontiers in strongly fortified posts. `Constantine abolished this security by removing the greater part of the soldiery from the frontiers to cities that needed no auxiliary forces.' Once there, he claimed that the soldiers became a burden on the communities and were themselves softened by the pleasures of urban life."
When not on campaign - and even at the most intensive periods of operations these were rarely conducted over winter - the comitatenses were dispersed in towns and cities within the provinces. It is doubtful that more than a brigaded pair of units were often stationed in one place. This spread the burden of feeding them and made it harder for the units to join together and back a usurper. In addition, it provided trained soldiers to man the city walls in the case of a sudden threat from a foreign enemy or a rival for imperial power. There was nothing especially new about stationing troops in or near towns. This had been common in the eastern provinces in the first and second centuries, although there was a well-established literary cliche that maintained it had an enervating effect on them.14
Yet in the earlier centuries army units had normally lived in their own barracks within or near to cities. This does not seem to have been the case with the cornitatenses - although admittedly the archaeological evidence for the layout of most towns in the fourth century is extremely limited. Instead, they were billeted in civilian houses, and legal documents talk of officials painting on the door posts the number of men and the unit from which they should come. Throughout history billeting has frequently caused friction between soldiers and civilians. From a military point of view, the dispersal of units in small groups over many separate dwellings was not conducive to good discipline. In their purposebuilt barracks the units of the first- and second-century army had been concentrated in one place under the close eye of their officers. They were provided with good sanitation, exercise and bathing facilities, as well as hospitals for their sole use, and had parade grounds and training areas readily available. Facilities in cities and towns were far more limited and not for the exclusive use of the military. Even the largest city might well struggle to find good stabling for the 500-1,000 horses mustered by a couple of cavalry regiments.
Distributing the comitatenses in cities was the easiest solution for the government, but was scarcely the best way to keep them in good con dition. Military training was and is not a simple thing, permanently instilled once it is learned, but something that must be constantly repeated. As important was physical fitness - essential for the marches required on campaign, let alone actual combat. Both were harder to maintain when the army was split and billeted in civilian settlements. There was also inevitably a delay in concentrating the units before a campaign could be begun. The army may have maintained some pack and baggage animals permanently - and if so these were an extra burden to the communities on top of the cavalry mounts - but still needed to requisition or purchase many more to carry its food and other stores in the field. All this took time and faced the added complication of much of it being controlled by bureaucracies entirely separate from and with different priorities to the army.
It is reasonable enough to call the comitatenses field armies. They were more mobile and should usually have been more effective fighting units than the limitanei, at least for large-scale operations. Yet, on the whole, there was nothing particularly innovative about them, certainly nothing that
would justify calling them elite. The physical requirements were the same as for service in the earlier army, and later in the century even these would be reduced. Over the course of time, some units of limitanei were attached permanently to the field forces, receiving the halfway status of pseudocomitatenses. This suggests that there was no stark distinction in the military potential of the two grades of troops. In the end, troops were as effective as their training, leadership, tactics and equipment allowed. Only the Persians came close to matching the army tactically, and barbarian armies were markedly inferior. The factory-produced equipment of the fourth-century army has a more functional look than the armour and weapons of the early empire. Both the pilum (heavy javelin) and short gladius (sword) had fallen out of use. Instead, the standard weapons were a long-bladed spatha (sword) - previously only used by cavalrymen - and simpler spears suitable for both thrusting and throwing. As an individual, the Roman soldier was still a well-equipped fighting man. Infantry tactics were probably a little less aggressive, but remained effective. The fourth-century army won the great majority of the battles it fought.15
The standards of training and quality of leadership of the fourthcentury Roman army inevitably varied - as indeed they had done in earlier periods. On average standards may have been a little lower, but it remained the only professional army in the known world. The demise of the 5,ooo-man legion removed one command level useful for operating and controlling very large armies in the field. It also meant that it was harder to support large numbers of specialists - engineers, architects, siege specialists, artillerymen etc. - within the army and pass on their experience to successive generations. The comitatenses had no permanent bases to act as depots and to maintain records of personnel, their postings, equipment and mounts. Records were still kept, but had to be moved continually if they were to remain useful to the unit. The same was true of soldiers. New recruits, convalescents or detached men returning to normal duty would have to travel to rejoin the parent regiment wherever it happened to be. The frequency with which a unit went on campaign would have steadily worn it down. Some men would be lost to enemy action, many more to sickness or detachment. This meant that large numbers of men may have existed and been rightfully paid by the state, but would not actually be present with their unit when it went on campaign. The probability that most units were heavily under strength most of the time makes it all the harder to estimate their full theoretical complement."
How Rome Fell: Death of a Superpower Page 26