The Standard Legionary Combat Formations in 275 according to Modestus
There exists a military treatise by Modestus, which is addressed to the emperor Tacitus. The author of this treatise is usually thought to be have used Vegetius’s Epitome of Military Science as a source, or alternatively it is thought that it is a fifteenth century forgery, 1 but this view is not shared by all historians and it is because of this that I have included a discussion and analysis of it here.
Its authenticity receives support from the circumstantial evidence. Firstly, Tacitus was a man who did not possess any military experience, so he would certainly have needed such advice as Modestus’s treatise offers. Secondly, the text is not an exact carbon copy of Vegetius, 2 so it is possible that both authors have used the same source or sources for their text. Thirdly, it is possible that Vegetius has used Modestus as one of his sources.
My purpose is to offer a possible glimpse into the state of Roman military science as it stood at the beginning of Tacitus’s reign by offering a description and analysis of the material included by Modestus with the assumption that it is a genuine treatise and not a forgery. If the legions (the so-called Parthica legions) as described in Modestus and Vegetius were created under Septimius Severus as I have suggested in my biography of Caracalla, it is possible to think that the legionary tactics and equipment that these two treatises describe were also used during the third century.
The standard modern edition of Modestus is ‘Modesti libellus de vocabulis rei militaris ad Tacitum Augustum (Estudio de la transmission manuscrita y edición crítica)’ by Tomás Gonzales Rolan and Ana Moure Casas, in Filologia Clasica Vol. XX (1986– 7), Universidad Complutense Madrid, and it is this edition which is used here. The following discussion concentrates only on the main points.
The correspondences between Modestus and Vegetius have been analyzed often and the following list is from Rolan and Casas (p.289):
| Modestus | Vegetius |
| 1.1–2 | 2.1.5–13 |
| 1.2–3 | 2.1.2–8 |
| 2 | 1.1.26 |
| 3 | 2.2 |
| 4 | 2.4 |
| 5 | 2.6 |
| 6 | 2.7 |
| 7 | 2.8 |
| 8 | 2.9 |
| 9 | 2.13 |
| 10 | 2.14 |
| 11 | 2.15 |
| 12 | 3.14 |
| 13–14 | 2.16–18 |
| 16 | 2.22 |
| 16 | 2.22 |
| 17 | 3.8 |
| 18 | 3.16 |
| 19 | 3.24 |
| 20 | 3.17 |
| 21 | 3.26 |
| 22 | 3 praefatio, 14–18 |
| 23 | 1.28 |
Modestus began his treatise (1.1–3) with the standard definitions of what constituted the Roman military forces. It consisted of three basic elements which were: cavalry (equites), infantry (pedites) and navy/fleets (classes). The cavalry consisted of the alae (wings), vexillationes (detachments) and equites legionarii (legionary cavalry). A comparison with the sixth century author Lydus (De Magistr. 1.46) suggests the probability that the cavalry alae (ilai) consisted of 600 horsemen and the vexillationes of 500 horsemen. Lydus does not include equites legionarii separately but includes cavalry units called turmae, which consisted of 500 mounted archers. It is therefore possible that Lydus’s turmae are actually the units of legionary cavalry, which consisted of smaller 32-horsemen (plus one decurio) units which were also called turmae. The alae would presumably have been the cavalry units of the regular auxiliary forces, while the vexillationes would have consisted of native/tribal units of cavalry that had been enrolled into the army.3 The infantry consisted of legions (legiones) and auxiliary forces (auxilia) so that the latter consisted of the socii (allies) and foederati (treaty-based allies). The division of auxilia into two types of forces is valuable because it suggests that the units of socii were probably the regular auxiliary units while the foederati were primarily treaty-based tribal forces which could be based either inside the Roman Empire (as soldier-farmers in return for military service) or as allies outside the borders in return for payments.
The tirones (recruits) were to be trained to fight in a single line (simplex acies), double line (duplex acies), acies quadratum (hollow square) and triangulum/cuneus (triangle/ wedge). This suggests that the standard battle formations at this time were the single phalanx, double phalanx and hollow square/oblong formations and that the wedge was the standard tactical formation which was used to break through enemy formations. The manoeuvres used in the forming of these arrays would also have enabled the use of other combat formations and manoeuvres and one may assume that these were also known and used even if they were not included in this list of training manoeuvres by Modestus, because we know they were used during the reign of Aurelian. Regardless, the list (2.1–2) given by Modestus here is still valuable because it gives us the likely standard combat formations used at the time. It is also valuable for another reason. It gives us the basic combat manoeuvres that the Romans expected their legionary infantry to be able to use, because Modestus describes only after this (3.1–2) the way in which the auxilia were to be used. According to Modestus, the auxiliary forces were to be used only as light-armed forces (levis armatura) for the legions, because these forces came from different places and had different habits so they did not have the same discipline, equipment and way of fighting. The auxilia were never to form the principal fighting force of the army. It was an auxiliary service as the name implies. The information that Modestus provides (p.4) of the size of the ideal army is antiquated because he states that all authors agreed that each consul was never to lead more than two legions reinforced with auxiliary forces against an enemy. The above is basically the same as in Vegetius 1.26.
The Standard Legionary Combat Formations in 275 according to Modestus
The legionary structure and its combat formation, to be found in Vegetius (2.6), is also partially antiquated. However, there are some significant differences between these two accounts. I will begin with Modestus’s version (5.1–7.3) after which I will elaborate the differences and conclusions.
The legion consisted of ten cohorts. The first cohort consisted of 1,105 footmen and 132 horsemen, so it had more men than the other cohorts. The men of the first cohort were considered to be of higher quality than the others because it was in charge of the legionary eagle standard (the aquila carried by the aquilifer) and the imperial standard depicting the emperor (the imago carried by the imaginifer/imaginarius). It was called cohors milliaria (milliary cohort) because of its size. The first cohort was placed on the right wing of the first line. The cohorts from the second to the tenth, all had 560 footmen and 66 horsemen, and were therefore called cohors quingentaria (quingentarian cohort). The order of cohorts in the first line from right to left were one to five, and in the second line from six to ten. The third cohort was to consist of stronger men because it stood in the centre and likewise the fifth was to have energetic soldiers because it was on the left flank. The sixth cohort was to consist of solid young men (iuniores) because it was behind the first cohort and therefore guarded the standards. The eighth was to have spirited men because it stood in the centre and the tenth was to consist of aggressive warriors because it held the left flank. The total number of men in a legion was therefore 6,105 and 726 horsemen. There were never to be fewer soldiers than this in a legion, but it was acceptable to have a larger force by adding other milliary cohorts to it. This last instruction allowed the commander to compose a generic legion out of legionary detachments, which was stronger than the regular legion.
The above text is basically the same as in Vegetius (2.6), but there are discrepancies in the figures. In Vegetius the cohorts second to the tenth had 555 footmen and 66 horsemen each while in Modestus’s version they had 560 footmen and 66 horsemen each. This discrepancy can be explained by adding to the figure of 555 the supernumerary standard-bearers, heralds and musicians for a total of 560 men. In fact, Modestus’s own figures are off in this respect because he claims that the total size of the force was 6,105 footmen and 726 horsemen when in reality with 560 footmen his total should be 6,145 footmen and 726 horsemen. In other words, the total 6,105 that Modestus gives is based on the same figure as in Vegetius, namely 555 footmen per cohort, and it becomes the 6,145 only when it is counted as 560 footmen.
Modestus (6.1–7.3) and Vegetius (2.7–8) also give us similar but still slightly different versions of the legionary centurions. I will begin with Modestus’s version.
The primus hastatus, who commanded 200 men, was located in the second line. However, as we shall see from Vegetius’s text he was actually one of the commanders of the first cohort. The princeps of the first cohort commanded 150 men. Ten centurions were in charge of the first cohort.4 In addition to these, there were centurions who commanded single centuries which were now called centenarii. Each of the second to the tenth cohorts had five centurions so that the total number of centurions was 55. Since the cohorts two to ten made up 45 centurions it is clear that the first cohort must have had 10 centurions.5
Vegetius (2.8) gives a different rundown. According to him, the first cohort was led by the following five men: 1) primus pilus/primus princeps who commanded four centuries; 2) primus hastatus who commanded two centuries making altogether 200 men in the second battle line. He was also known as the ducenarius; 3) the princeps of the first cohort who commanded one and a half centuries making 150 men; secundus hastatus commanded also 150 men; triarius prior commanded 100 men. The rest of the cohorts were commanded by centurions now called centenarii, five each so that there were altogether 55 centurions. In other words, Vegetius’s text implies that the above-mentioned five higher ranking centurions of the first cohort would probably be part of the 10 centurions that are required for the first cohort for the total of 55 centurions per legion.
These versions are irreconcilable, but if one still tries to reconcile them then one may assume that it is possible that Vegetius has included extra officers for the first cohort because the first reference to the practices of the period occurs in the context of primus hastatus, who were called ducenarii, and that both authors have made the mistake of placing this officer in the second battle line (ducebat in acie secunda) unless the implication is the primus hastatus was actually an officer who commanded also at least one century placed behind him in the sixth cohort. My suggestion, however, is that the primus hastatus the princeps of the first cohort were just higher ranking centurions so that they received salaries commensurate with the number of men officially under their command. The reasons for the conclusion that the numbers of men commanded by the higher ranking centurions refer to the pay grade are: 1) it is impossible to reconcile the commands of 200 men and 150 men with each other unless the centuries in question were divided accordingly; 2) both texts claim that there were 55 centurions altogether. The other possibility is that Vegetius is correct and that the five higher ranking centurions were just centurions who received higher pay according to the official number of men under them. In light of the evidence, it is actually likelier that Vegetius is correct to include the other ranks so that one may assume that Modestus (if he was the author) either made omissions or his treatise was later carelessly copied so that some sections were lost.
The legionary rank-and-file organization in both Modestus (7.3; 9.) and Vegetius (2.8) is the same. Both state that the centuries were organized into units of tens commanded by decani (sing. decanus) and that the decani were also called caput contubernii. The ten-man group was also called contubernium (tent group) or manipulus (maniple). From other sources, we know that the fighting component of the contubernium consisted of eight men with the implication that the two extra men per ten-man group were one tiro-recruit and one servant, but it is also possible that the two extra men per file/tent-group were light-armed men so that we should add to these figures the servants and recruits.
The higher command structure of the legion (Modestus 6, 8) was as follows. The legati (sing. legatus) of the emperor had been in charge of the legions and auxiliaries, but their duties were overtaken by the time of Modestus by the magistri militum (Masters of Soldiery) who belonged to the illustres-rank. Each of these commanded not only two legions but more legions. The magistri referred to by Modestus are not necessarily anachronistic for this era thanks to the changes instituted by Gallienus (see my bio of him). The praefectus legionis was the successor of the legatus because he was in charge of the legion. The tribunes, centurions and soldiers followed his orders. The tribunes performed judiciary functions on his behalf. Arms, horses, clothes and food supplies were the responsibility of the praefectus legionis, as were discipline, punishment and exercises of the infantry and cavalry. Below the legionary prefect served the tribunus maior who was appointed by the emperor. As noted in the text, the tribune (i.e. the tribunus maior who was usually a member of the imperial bodyguard) could also be used as acting commander of the legions instead of the prefect. The tribunus minores (sing. tribunus minor) received their position by being promoted through the ranks. Ordinarii were those who commanded the first units in battle (ordines). The list of ranks is basically the same as in Vegetius (2.7, 2.9) but omits the discussion of praefecti castrorum and praefecti fabrorum included in Vegetius (2.10–11).
Modestus (9–10) states that each legion had an eagle standard (aquila) carried by aquilifer, each cohort had a draco-standard carried by a draconarius, and each century had a vexillum-standard. Each century was commanded by a centurion, now called centenarius, who had a helmet with a crosswise plumed silver crest. The soldiers could therefore recognize their century both from the vexillum and the crosswise plumed helmet of their centurion. The centurions were required to be robust and of the right stature and were also to be good throwers of hasta-spear and missiles. The centuries consisted of the ten- man contubernia under their decani, which were also called manipuli (maniples).
The 32-horseman turmae (sing. turma), each under its decurio (so that there were 2 x 32 horsemen plus two decuriones per standard cohort) formed the basic component of the legionary cavalry. The decurio was to be agile, good at mounting his horse, dressed in lorica-armour (body armour, cuirass) and fully equipped with weapons. He was expected to be a good horseman, good with the contus-spear and a good archer. He was also expected to be able to teach all the necessary cavalry skills to his own turma. The key point here is the expectation that all legionary horsemen were expected to be both lancers and mounted archers – a requirement which can be found in Arrian (Techne Taktika 34.1–44.2; Ektaxis kata Alanon) which confirms that the Romans continued to attach great importance to the versatility of their cavalry forces.
The above information is basically the same as in Vegetius (2.13–14), but Modestus omits some of the material contained in Vegetius.
Modestus (11–14, 18–20) includes two basic variants of the combat tactics, which can also be found in Vegetius (2.15–17, 3.14–17, 3.24). The first of the battle arrays was the old standard legionary duplex acies for one legion, the principle of which could be easily extended. Note however that the above-mentioned training scheme suggests that this was not the only type of combat formation that Modestus and Vegetius expected the old style legions to be able form. They were also expected to be able to fight as a single phalanx, hollow square/oblong and wedge.
Vegetius (2.15) adds here the light-armed
Vegetius (1.20, 2.16) adds here the triarii who could be interpreted as reserves
The first line consisted of cohorts 1–5 with cavalry placed on the flanks. The ordinarii and other officers (caterique principales), who fought in the first line in front of and among the standards (signa), were called as principes. They were considered to be heavy-armed (gravis armatura), equipped with helmets (pl. cassides, sing. cassis), cataphract-armour (sing. catafracta, pl. catafractae), shin-guards (pl. ocreae, sing. ocrae), scutum-shields (pl. scuta), longswords (gladios maiores, spathae), shortswords (gladios minores, semispathae), five darts (plumbatae) placed behind the scutum-shield, and two missiles/javelins (bina missilia), one long and one short. The long missile had a triangular iron head nine inches long with a shaft (hasta) five and a half foot long. It used to be called pilum (heavy javelin), but was now called spiculum. This was designed to pierce the scuta of the infantry and the loricae of the cavalry. The short javelin had an iron head five inches long and a shaft of three and a half feet long. It used to be called vericulum, but its new name was verutum. Modestus omits here the references to the light-armed (levis armatura/ferentarii/ exculcatores: armaturae, sagittarii, funditores, tragularii) behind the first line, which can be found in Vegetius (2.15).6 Vegetius is probably correct to add these to the formation, but obviously the light-armed would not have been part of the legionary array proper but a separate force of light-armed under their own commanders, which according to Modestus would have consisted of the socii and foederati. It should be noted however that legionaries were trained to use all of the weapons mentioned so it was possible to use the legionaries in like manner when deemed necessary. The second line consisted of cohorts 6–10 and was called the hastati. These were armed in the same manner as the first line.
Vegetius (1.20, 2.16) adds to this list the antiquarian triarii as a third line behind the second line. It is impossible to know whether this existed or not, but it is possible to reconcile this by assuming that the triarii would have been separate reserves, for example among the baggage train or in front of a marching camp that the Romans used as required by the situation. Vegetius (3.17) and Modestus (20) state that there were always to be subsidia (reserves, sing. subsidium) infantry and cavalry behind on the flanks and middle, which may be the meaning here. It should be noted however that the extant evidence for Roman battle arrays suggests that there were usually no extra reserves for the duplex acies because the second line in itself was usually considered as a reserve, and it is therefore quite possible that Modestus did not in fact make an omission here.
The second of the variants (Modestus 12–14) was a single line consisting of six ranks (ordines), which presumably had cavalry wings (Modestus 18), and reserves of cavalry and infantry behind (Modestus 20). This is the most problematic piece in both Modestus (12–14) and Vegetius (3.14–17) because it is difficult to reconcile with the other information that we have of Roman battle arrays. My educated guess, however, is that it was used by the Parthian legions that had been formed by Septimius Severus, and probably by other new legions that were raised after his reign. We have no concrete evidence for this structure outside Modestus and Vegetius, on top of which there is the problem of what was the size of the file/tent-group (contubernium) if it consisted only of six men when it had previously consisted of ten men out of which eight men were designated for combat duties. Does this mean that the tent-group still remained the same, but so that only six men out of it were placed in the battle line, the rest being placed among the baggage and/or in the reserves? In my opinion, if the array reflects the truth in any way, we should interpret the six-man file to have consisted of one half of the contubernium so that it had four legionaries plus the two light-armed who would not have been part of the heavy infantry contubernium. Two such files would therefore have made up one traditional eight-man contubernium of heavy-armed (plus the recruit and servant left behind in the camp) and half of a contubernium of the light-armed.
The Stonewall (Murus), the Heavily-armed (Gravis Armatura)
1) The first rank (ordo) consisted of men the ancients called the principes. Modestus describes their equipment only later and these references make it clear that the men wore at least cataphract-armour, helmets, scuta, spathae, lanceae and spiculi.
2) The second rank consisted of the best soldiers otherwise called hastati who were equipped with cataphract-armour, and spiculus-javelins or lancea-spears. Vegetius (3.14) states that in the second line were the cataphracted sagittarii (archers) and the best men armed with spiculi or lanceae.
– The omission of the archers in the second rank in Modestus actually makes sense in light of the description of how the two front ranks fought, but I would not completely preclude the possibility that there could have also been men armed with bows because Syrianos Magistros (Peri Strategias 36) states that when the infantry faced cavalry the first two ranks were to shoot straight at the horses while the rest behind were to shoot at an angle. However, in light of the description of the way in which the first and second ranks fought (Modestus 12.6 and Vegetius 3.14), it is still likelier that Modestus’s omission is more accurate.Vegetius could easily have mixed the second and third ranks in his description. The interval between ranks one and two was six feet so that they could throw their spears with greater ease.
– The soldiers of these two ranks consisted of heavily equipped mature men who were confident and experienced. They stood like a murus (stonewall) in place and neither gave ground nor pursued the enemy, and fought with pila (sing. pilum).
The Light-armed (levis armatura/ferentarii)
3) The third rank consisted of the mobile armed men, of young sagittarii, and of good javelineers, which the ancients called ferentarii.
4) The fourth rank consisted of the very mobile shield-bearers (scutati expeditissimus), 7 young archers, and of those who were armed with javelins or martiobarbuli/ mattiobarbuli (lead-weighted darts) which were also called plumbatae.
– the third and fourth ranks were called light-armed (levis armaturae) and they always advanced in front of the battle array to provoke the enemy with javelins and arrows. If the enemy fled, they and the cavalry pursued them. If the enemy forced them back, they fled through the first and second lines and assumed their previous positions. The first and second lines fought with pila. Modestus has here only the javelins (prima autem et secunda acies cum ad pila, ut dicitur, ventum fuerit, totum sustinent bellum) to mean the mêlée, but Vegetius includes the fuller version with swords included (prima autem et secunda acies cum ad spathas et ad pila ut dicitur, ventum fuerit, totum sustinent bellum) which is of course more accurate as it means that the fighting was done with javelins and swords by the first and second lines who then sustained the fight. Modestus, however, adds a problematic instruction at 14, which states that levis armaturae/ferentarii and sagittarii and funditores (slingers) provoked the enemy in front of the first and second acies. The problem with this is that Modestus (and Vegetius) places the slingers at the fifth rank (see below). This same instruction can be found in Vegetius 2.17 in the context of the old legionary structure with cohorts so it is possible that Modestus has placed it in the wrong context. My suggestion is that both versions of Modestus are correct so that the fifth rank could be used either in front of the first rank or alternatively as a support force for the sixth rank if the enemy threatened from behind. I suggest that it was up to the commander to decide whether to send men from the fifth rank forward (see next) at the same time as the third and fourth ranks (the so-called light-armed) advanced to skirmish, or to keep them where they were.
The Fifth Rank
5) The fifth rank consisted of the ballistarii/balistarii (probably users of manuballista or arcuballista), funditores (slingers), tragularii (in this case probably users of tragula-javelin), fustibalatores (staff-sling users). The young recently recruited fighters who did not possess shields were posted in this rank so that they used either hand-thrown stones or javelins. Vegetius (3.14) has basically the same list, but he elaborates the material by stating that in the fifth rank were placed the carroballistae (horse-drawn carts with ballistae), manuballistarii, fundibalatores, and funditores. In other words, Vegetius understood the ballistarii to be artillerymen using the carroballistae. Similarly, Vegetius understood the tragularii to be the manuballistarii of his own day. It is therefore quite possible that both were working from the same source so that Vegetius has elaborated the text on the basis of the terms used during his day. If we assume that Vegetius was correct in his interpretation, then the use of the drawn artillery carts would mean that the fifth rank was not a real rank of soldiers in the traditional sense. However, in my opinion it is clear that Vegetius’s elaborations are incorrect, and he also proves this to be the case when he explains the distances between the ranks and files (3.15) which clearly prove that we are here dealing with a real fifth rank. Vegetius states in that section that each file in the formation occupied three feet and each rank occupied six feet plus one additional foot so that the depth for six ranks was 42 feet. In short, we should rather accept what we find in Modestus’s text so that the ballistarii of Modestus’s time did not mean the artillerymen of Vegetius’s day, but rather the crossbowmen equipped with the arcuballistae or manuballistae while in this case the tragularii meant the javelin-throwers which would be otherwise missing from the list of skirmishers. The lightly-equipped fifth rank belonged to the ‘heavy-armed’ because they are not included among the light-armed (the third and fourth ranks) by Modestus and Vegetius. This text is also valuable for another reason. It shows where the Romans placed their recruits (the tirones) when they were included in the battle array.
The Sixth Rank = Heavy Infantry Reserve
6) The sixth rank consisted of strong soldiers who were equipped with scutum shields and every type of defensive and offensive equipment. The ancients called these triarii and formed the ‘last rested reserve’. In my opinion it is clear that this posting of the ‘triarii’ as the last rank made the formation two-fronted so that it was possible to face enemies from the front and behind simultaneously. In short, the triarii did not only form the ‘last reserve’ as stated by the sources but also a second front towards the rear when needed and probably in such a manner that the fifth rank would have served as its light-armed in such case.
Equipment worn by the front-rank fighters, signiferi and centurions
Modestus (13) continues the account by stating that all those in front of the standards (Vegetius 2.16 elaborates by calling these antesignani) and the signiferi wore less armour and wore helmets covered with bearskins to frighten the enemy. The centurions wore cataphract armour, scuta, and helmets with silver crosswise crested plumes.
Modestus (14) describes how the above array was to be used but he has taken it from the section (in Vegetius 2.17) which describes the old-style legion so it is possible that he has made a mistake. This adds to the list of skirmishers (ranks three and four) also the slingers. It is quite possible that this was so because it would be odd if the Romans had not used their slingers in front of their array like they used the other light-armed men. This section states that the first, second, and sixth ranks stayed in their place while the ferentarii, levis armaturae and sagittarii and funditores advanced in front to provoke the enemy. The funditores meant only a part of the fifth rank, and since it is known that the slingers needed room to operate it is indeed quite understandable if these were sent separately from the rest. Regardless, I would still suggest that it is possible that the entire fifth rank could also be sent forward to skirmish at the same time as the third and fourth ranks, if the commander so desired. If the enemy forced the light-armed back, they retreated behind the first and second ranks and these stood like a wall against the enemy. The pursuit of the enemy was once again to be performed by the light-armed and cavalry.
M. Diverse instructions
After the above, Modestus included (15–17) diverse instructions before he returned to tactical issues (18–20) presumably meant to be used with the six-ranks formation.
The first of these general instructions (15) is that the shields of every cohort were to be painted with different colours and that each soldier was to have his name, cohort and century painted on the inside of the shield. This enabled the soldiers to recognize each other with greater ease and is the same as in Vegetius 2.18.
The second (16) is that each legion was to have tubicenes (trumpeters using the tuba straight trumpet), cornicenes (cornet players using the cornu-horn made from the horns of the wild ox), and bucinatores/buccinatores (horn players after the curved bucina military horn/trumpet). The tubicenes called the soldiers to battle and it also called them to retreat. The cornicenes sounded signals to the standard-bearers but not to the soldiers. In short, the soldiers were ordered by the tubicenes and the standard-bearers by the cornicenes. The bucinatores sounded their horn to signal classicum, which was a fanfare used to announce capital punishment or the presence of the emperor. When the soldiers were to go to guard duty (ad vigilias) or to build agrarias (outpost of the camp), or for military exercises, or for any assignment outside, this was announced by the tubicenes; and its ending was also announced by the tubicenes. The cornicenes ordered the standard-bearers either to move or to halt. In sum, the officers used these musicians to order the soldiers to fight, halt, follow, or to return as needed. This is the same as in Vegetius 2.22, but Vegetius also includes a fuller discussion of the different ways to command the soldiers at 3.5 which is not specifically included in Modestus. However, Modestus still refers to, or implies the use of, all of these (voice, horns, standards, plumes) in his treatise.
The third (17) concerns guard duties in the camp. Each of the centuries was to detail four footmen and four horsemen for guard duty during the night. Guard duty for each group of guards lasted for four hours and the ‘night’ was divided into four parts. The guards were dispatched to their duty by the tubicenes and then recalled to their tents by the cornicenes. This instruction is included in a longer discussion of the organization of marching camps by Vegetius 3.8. In Modestus it follows logically after the previous discussion of the ways in which the horns/trumpets were used, and it is therefore possible that this piece of information had originally been included in a treatise which dealt with all of the different uses of the horns/trumpets which has been retained in Modestus, but placed elsewhere by Vegetius.
Both Modestus (18) and Vegetius (3.16) naturally place the cavalry on the flanks as most ancient military treatises did. The loricati (armoured horsemen) and contati (those carrying contus) were placed next to the infantry. The sagittarii and others who did not carry armour were posted further out. The stronger (‘fortioribus’) cavalry protected the flanks of the infantry, while the faster (‘velocioribus’) and lightly-equipped (‘expeditis’) were to scatter and disorder the flanks of the enemy formation. The dux (general) was also required to know which cavalry unit to place against which enemy drungus (a throng meaning irregular array) or globus (a crowd meaning a detached unit). The reason for this was that certain types of troops were better against certain types of troops than others. Vegetius 3.19 equates globus with drungos so it was probably the same type of array. If the Roman cavalry was inferior to the enemy, Modestus instructed the commander to place mobile infantry equipped with light shields and trained for this duty among the cavalry. The name for these was the velites. The velites were used in such a manner that one young soldier, who was a good runner and equipped with a light shield, sword and javelins/ missiles, was placed between two horsemen. This is basically the same as in Vegetius 3.16 even if there are some slight differences in the way the sentences are structured.
Modestus follows this with a description of how to fight against elephants (19), which is essentially the same as the latter half of Vegetius’s chapter 3.24 even if the latter is longer and slightly different. If one speculates about the inclusion of this at this place, it is possible to use it as a proof of the accuracy of Modestus’s treatise because such a summary as Modestus claims to have made for Tacitus would definitely have been required information for the inexperienced Tacitus, because at the time of his death Aurelian had been on his way against the Persians who used elephants. It is quite plausible to think that Modestus’s treatise was written before it became apparent that the first enemies which Tacitus had to deal with were the Goths and Heruls which Aurelian had assembled against the Persians, and even then the instruction of how to fight against elephants would not have been out of place because Probus was subsequently forced to deal with this question immediately after assuming power and was also planning to begin the long planned campaign against the Persians when he was murdered. The above instructions for the use of cavalry units against detached enemy cavalry drungi and globi would also fit the circumstances in which the fight was to be conducted against the Persians.
The information about the elephants in warfare is as follows. The elephants frightened the enemy with their size, horror of their trumpeting (barritus horrore), and by the novelty of the spectacle. Pyrrhus, Hannibal, Antiochus and Jugurtha had used them against the Romans. The Romans had devised several different means against the elephants as a result. The first was to cut off the trunk with a sword as had been done by a centurion from Lucania. The second was to use cataphracted horses to draw a war chariot and place clibanarii (heavily-armoured men) armed with sarissae (very long spears – longissimos contos) and use them to thrust into the elephant. The third was to send cataphracted legionaries (cataphractos milites) with iron barbs attached to their arms, helmets and shoulders so that the elephants were unable to seize them with their trunks. The implication is that these soldiers also wore armour on their arms (manicae?) and probably also on their legs, so they may have looked like the gladiator crupellarius or ‘arbelas’ or medieval knight with the addition of spikes.xs
Fully Armoured gladiators:a drawing by Duruy of a relief depicting a gladiator now at the Louvre, which Carter identifies as an ‘arbelas’ gladiator who was armed with a knife and arbelos (semi-circular shoe-maker’s knife). The original image in the Louvre has a visible trace of arbelos on the left hand which is not visible in Duruy’s drawing, but I have restored it with a line to the image.
Fully Armoured gladiators:Author’s drawing of a bronze figurine from Vertigny, which is usually identified as crupellarius. It is possible that Modestus and Vegetius meant soldiers equipped like these gladiators with the addition of spikes against the elephants.
The fourth method, the use of velites against the elephants, was the principal tactic that had been used by the ancients. The velites were young, lightly-equipped, agile men, mounted on horses armed with javelins. They were therefore much like the eleventh century peltasts who were infantry in antiquity but light-armed horsemen in the eleventh century (see Syvänne, 2010). The velites rode their horses back and forth alongside the elephants and peppered them with lanceae (a lance with two variants, long and short), or maiora spicula (heavy javelin). The reference to a long spiculum is interesting because it suggests that there existed also a longer variant of the spiculum/pilum, which can possibly be equated with a cavalry spear but with the likely difference that these two types had a different point. These were at their best used in quantity, thrown in volleys simultaneously at the elephant. The fifth tactic was to use slingers and staff-slingers. These killed the Indos8 who drove/rode the elephants and the men in the towers. The sixth tactic was to open up the formation (agmen) of legionaries to allow the elephants pass through, after which they were surrounded from all sides with a globus so that the magistri militum (masters of soldiers)9 could capture the elephants with their drivers. Vegetius adds here a seventh tactic which was to use the carroballistae behind the battle line to transfix the elephants with their missiles. This is consistent with the above where Vegetius has these carroballistae in the fifth line while Modestus does not. It is not certain whether the omission by Modestus was purposeful or just accidental because we know that the Romans did use carroballistae as part of their battle line during the third century, so it would have been quite possible to use them in the manner described by Vegetius. One possibility is that Modestus assumed that this knowledge was not necessary, because the carroballistae crews, when present, would have targeted the elephants anyway without having been ordered to do so. Modestus described only how to use the six ranks of the phalanx with their cavalry wings against the elephants.
Modestus (20) like Vegetius (3.17) stated that the dux posted chosen footmen and horsemen with extra vicarii, comites and tribuni behind the acies to the wings and the centre as reserves. In other words, the ‘real last reserve’ was not the sixth rank triarii, but these. If the enemy attacked vigorously the reserves were to rush forward to block it. The cuneus (wedge) and forfex (pincer) arrays were formed by using the reserves behind for this purpose. If the Romans had few men, it was necessary to make the reserve stronger. Modestus omits the discussion of the serra (saw) array and the use of the globi against globi, which are mentioned by Vegetius. Similarly, Modestus does not include any discussion of the different unit tactics (serra, globus/drungos, cuneus, forfex, orbis)10 nor of the seven different battle formations (lateral phalanx/rectangle, right oblique, left oblique, forward angled array, forward angled array with light infantry posted in front, right wing sent in advance to outflank, and use of terrain) included in Vegetius 3.19–20.
Modestus (21) includes two instructions on how to prevent the enemy from learning what the Romans had planned. Enemy spies/scouts (exploratores) inside the camp were to be captured by calling all men inside the tents. The commander was to deliberate matters with many in councils, but to keep the number of trusted men small. This meant that the enemy got several possible versions if discussions leaked, but not the real decisions because the number of trusted men remained small. The list selects only two examples from a large number of maxims included in Vegetius 3.26.
Modestus (22) states that as ordered by the invincible emperor his intended purpose was to write a treatise based on scattered ancient authors and that he had done that as well as his modest talents allowed. This was a standard topos among this class of authors and is the same as can be found in Vegetius (3 praefatio) but with the difference that Vegetius has much longer discussion.
Modestus (23) ends his treatise with a general discussion of military art. According to him, the passion for war and the lands which produced the Lacedaemonians, Athenians, Marsi, Samnites, Peligni and Romans still produced strong men. He also stated that Epirotes were at one time powerful, and that the Macedonians and Thessalians had defeated the Persians so that they marched to the borders of India. The Dacians, Moesians, and Thracians were always so warlike that the fables told that Mars was born among them. Modestus commiserated that it would take too long to enumerate the strengths possessed by all of the provinces, and that the long peace had caused men to turn to civilian professions and forget the practice of military training. The interesting point here is which nations Modestus names. They are all territories located in Italy, Greece and Balkans. The implication is that the treatise, which Modestus (and Vegetius, see below) had used for this, was probably written during the reign of Gallienus because it was during his reign that these areas formed the only source of recruits for him. It is also probably not a coincidence that the text refers to the pagan god of war Mars.
The above is basically the same word for word as the middle portion of Vegetius 1.28, but again Vegetius has a longer discussion. Vegetius also promotes the training of native recruits in the same context because it was cheaper to the train one’s own men rather than to pay foreigners to fight. It is probable that this is a later addition of Vegetius which refers to the problems of his own day when the Romans did indeed pay foreigners to fight on their behalf.
The above discussion has referred to the new type of legion which was deployed as a phalanx of six ranks for combat, which I have speculated to have been introduced by Septimius Severus for his Parthian legions on the basis of the unit structure.
The basic building block of this legion remained the same as before. It was the century, but its strength had been changed to suit the new tactical concept. We can calculate its strength by dividing the figures 555 (Vegetius) and 560 (Modestus) by five (the number of centurions). As noted above, Modestus’s figure includes the supernumerary men so that the division should be made according to Vegetius’s figure. This gives each century 111 men. The organization behind this is that there were 108 legionaries deployed six deep (18 files x 6 ranks = 108) plus optio (second-in-command), vexillarius (standard-bearer with vexillum; could also be called signifer carrying a signum) and centurio for a total of 111 men. Even if the basic structure of the file in combat had remained practically the same as before, 11 these numbers actually imply one major change, namely that now the light-armed had been added to the legionary numbers whereas in the past these had previously been separate and classed as auxiliary forces. The attached diagram gives one possible way the soldiers (numbers 1–6 show ranks), vexillarius (V), optio (O) and centurio(C) could have been deployed for combat.
The cohort formed the next unit size. It consisted of the above-mentioned centuries for 555 men with the NCOs. We should add to this figure tubicen, cornicen, draconarius, vicarius (second-in-command to tribunus) and tribunus for a total of 560 men. I would suggest that the bucinatores were not included in the regular cohortal structure because they were needed only on very special occasions. The milliary cohort would have had 1,110 men plus the supernumeraries.
The legionary cavalry in its turn probably consisted of 22 turmae of cavalry for 704 horsemen plus 22 decurions, 10 musicians, 5 standard-bearers, and 5 centurions for a total of 746 horsemen.
The legion consisted of the above-mentioned cohorts and of the milliary cohort so that the total size for the legion was 6,100 footmen plus the supernumeraries and 726 horsemen plus the supernumeraries. With four legions the battle array envisaged by Modestus would have looked something like in the attached diagram. The above also explains why we find heavy-armed legionaries deployed three deep in Josephus (e.g. BJ 2.173, 5.130–1) in a situation in which the contubernium (tent-group/file) consisted of eight soldiers, one recruit and one servant, as dictated by the size of the tent. The reason for this was that the Romans trained a third or fourth of their recruits to fight with the bows. In those situations in which we find the Romans using three deep or six deep formations of heavy-armed legionaries, they used the missing numbers of legionaries as archers. In other words, the three heavy-armed legionaries and one archer would have made up a half-file/half-tent-group, and the six heavy-armed legionaries and two archers, the entire fighting component of the file/tent-group.
