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Hierarchy in the Late Roman army, 300-550 AD

By Robert Vermaat

This article is about Late Roman army commands, under the understanding that the Roman army was not a clear-cut affair. First of all, we have to distinguish between ranks, titles and grades. This can be confusing, because sometimes titles evolved into ranks, and some ranks are without an earlier equivalent.


When we discuss the hierarchy of the Late Roman army, it's important to first get an idea of what we are discussing. Contrary to popular view, the Roman army was not an army comparable to modern armies. Changes were slow to be implemented, uniformity as we know it most probably did not exist, and standards like unit strength or uniformity in command structure was not the same all over the empire. The same goes for the 'new model army' that was developed by Diocletian and his successors (especially Constantine).

From the literary evidence (legislation, papyri, hagiographical and historical literature from historians such as Ammianus Marcellinus, bureaucratic documents such as the Notitia Dignitatum, tactical treatises such as the Strategikon or the inscriptions found throughout the empire, mostly on funerary monuments) we gather that Diocletian did not alter the structure of the 'old-style' units. These 'old-style' units such as legiones (regardless of these being later classed as palatinae, comitatenses or limitanei), cohortes and alae retained the same traditional internal structure and ranking system which they had during the Principate, and which remained the same until the 7th c. Their officers continued to be called tribunes, centurions and decurions. At the same time, 'new-style' units were created with apparently a different hierarchy of ranks and posts, limited to newly created units of the comitatenses, namely scholae, vexillationes, auxilia palatini and some cunei.


Ranks are the true steps on the ladder of command. We’ll try to filter out these ‘true’ ranks, even though this can be very difficult.
Although Maurikios only mentions the tribunus in his Strategikon, this does not mean that he abolished these titles in a reform (or reflecting a 6th-c. evolution), since many of them are mentioned in other sources up to the 10th c. That most are missing from the Strategikon may be due to the fact that everything not related to drill was omitted. Maurikios Greek ‘ranks’ may just be his own descriptions for operational roles, as they are descriptions of the command: ilarch, merarch (“commander of a meros” or division), hekatontarch (“commander of a hundred”), dekarch (“commander of ten”), pentarch (“commander of five”) or tetrarch (“commander of four”). Some of them are genre-terms or even coined by himself as a cover-all for the varying titles and ranks in use for some posts (such as ‘second-in-command’ possibly being the primicerius, vicarius or domesticus). But since we know that the 'old-style' units still existed next to the 'new-style' units in Maurikios' days, we can posssibly conclude from these generic names that the officers and nco's of the Roman army, although bearing different names, still existed. It means that both type of units looked similar and could be used next to each other at will. For example, a centenarius was the same function as the centurion, and both were still commanding a hundred men by the late 5th century.
Latin remained the language of the army until the 630s and Greek words and ‘translations’ (such as hekantontarch instead of centurio) also know from earlier sources such as Arrian, were probably not the nomenclature used in the ‘real-world’ Roman army.

Posts are temporary commands or duties, which could be held by men of different ranks, the seniority depending on the responsibilities and time for which the command could be held. Examples of such posts are the vicarius (in fact an ‘acting tribune’) and the domesticus (acting regimental chief-of-staff).

Titles are often confused with ranks. This is not surprising given the limited knowledge that we have of the Late Roman army and its structure. Add to that the fact that titles could be similar for civilian and military (such as the Magister), the inconsistency with which titles were used and the evolving meaning. In principle though, titles could be held by men of different ranks, and there seems to have been a rank-like hierarchy involved (such as Comites de facto outranking Duces).

Grades have to do with pay or denoting seniority and privileges, and several grades can be included in one rank. Another difference in pay grade was determined by the army class of a particular unit. Soldiers were paid more when they served in units that belonged to the comitatenses instead of the limitanei, and even more in the auxilia, scholae and palatini.

The only fourth-century list of these Late Roman regimental ‘grades’ or indeed a pay-scale is from Hieronymus writing ca. 386-7 (Jerome, Contra Johannem Hierosolymilanum episcopum 19 (PL23, 370);

  • tiro
  • eques or pedes
  • semissalis
  • circitor
  • biarchus
  • centenarius
  • ducenarius
  • senator
  • primicerius
  • tribunus

The only connection to the actual amount of money paid to (some of) these ranks and grades comes from an edict of April 13, 534 from Justinian issued to Belisarius in North Africa (Codex Justinianus I.27.2:19-36, which stipulates the salaries of military clerks in the five newly re-created African ducates after Belisarius’ victory over the Vandals.

One annona equalled 5 nomismata or solidi (one year of ration's worth), and one capitus equalled 4 nomismata or solidi (one year of fodder for the horse):

  • semissalis (one-and-a-half annonae, one capitus if cavalry, equals eleven-and-a-half nomismata)
  • circitor (two annonae, one capitus if cavalry, equals fourteen nomismata)
  • biarchus (two annonae, one capitus if cavalry, equals fourteen nomismata)
  • centenarius (two-and-a-half annonae, one capitus if cavalry, equals sixteen-and-a-half nomismata)
  • ducenarius (three-and-a-half annonae, one-and-a-half capitus if cavalry, equals twenty-three-and-a-half nomismata)
  • numerarius (four annonae, two capitus if cavalry, equals twenty-eight nomismata)
  • primicerius (five annonae, two capitus if cavalry, equals thirty-three nomismata)
  • assessor (eight annonae, four capitus if cavalry, equals fifty-six nomismata).

Most of these confirm the list of Jerome (the recruits and rankers are left out since there were no clerks of that rank), and from the amounts paid to the numerarius and the assessor we can concluded that these compare to the senator and tribunus respectively. Similarly, the rankers perhaps received one annona, one capitus if cavalry, equalling nine nomismata, and the recruit perhaps a half annona, one capitus if cavalry, equalling six-and-a-half nomismata.
We know from a law of Julian that a domesticus reived six capitus and therefore probably eight or even ten annonae or more (their children received already four annonae acccording to a law of Valentinian I). According to the Justinian Codex (I.27.2:20-21), a dux eceived a salary of 1.582 nomismata but they regularly pocketed annonae from the lower ranks as an extra source of income.


The magister was the replacement of the praefectus praetorium since the time of Constantine. The magister officiorum, a civilian official, commanded the scholae, but Constantine meant the bulk of the armed forces to be commanded equally by the magister peditum (general of the infantry) and the magister equitum (general of the cavalry). However, this system soon evolved. More magistri were appointed, such as the magister praesentalis or the magister in praesenti (magister commanding the forces in the presence of the Emperor), or regional commanders such as the magister militum per Gallias, per Orientem, per Thracias, etc.
It’s unclear if magister was originally a title or a rank, although it may have evolved into a rank. The substructure of the magistri is not known, also because the (apparent) titles were inconsistently used. Even in law codes, a single magister is addressed as magister equitum et peditum and comes et magister militum. Other such forms include the more known magister utrisque militae or the widely used simple magister militum. The men in these posts (or ranks) were addressed as Perfectissimi, Clarissimi, Illustrissimi, Magnifici and Gloriosi, and only outranked by the city prefects or the praetorian prefects.
In the East, the command structure remained decentralised, the praetorian prefects always remained more powerful than the magistri, and the Emperor always retained overall command. However, in the West the system became largely centralised – in the late 4th century, the magister peditum praesentalis obtained command over all the troops, and men like Arbogast, Stilicho and Aetius held almost supreme power. After 416, the magister peditum praesentalis held the title patricius. When the actual power of the Emperors began to decrease, this Patrician (notably men like Aetius and Ricimer) went on to become the de facto regent of the Western Empire.


When Constantine segregated the civil and military functions, the military commanders ceased to be civil governors (although in some cases there were exceptions). Provinces were henceforth commanded by praeses without military functions, while the troops were commanded by duces. There seems to have been no sharp distinction between comites and duces.

The comes (title) was originally a title (lit. meaning ‘companion’) for members of the entourage of the Emperor, not a rank. Later the title became known for several functions, both military as well as civilian. These functions were formalised by Constantine, by creating titles such as the comes sacrarum largitionum (finance minister), the comes domesticorum (commander of the protectores domestici).The military version of the title was the comes rei militaris, a vague title without a description of rank or importance, which could describe commands varying from minor frontiers to overall army command of a magister militum.
The comitatenses or field armies of a certain region always commanded by a comes (such as the comes Britanniarum) and was therefore possibly higher in status than a dux. A comes, however could, like a dux, also command a regional army group, indeed like the comes Litoris saxonicum per Britannias (count of the Saxon shore) or even frontier sections (law codes prove the existence of a comes limitis). Comites could also command vexillationes of the mobile field army in the field.

The dux (rank) was originally a title (lit. meaning ‘leader’) of an officer acting in a temporary capacity above his rank, commanding a collection of troops in transit or in temporary command of a single unit. From the third century, a dux became a regular officer. After Constantine, the dux commanded the provincial troops (the comitatenses and palatini falling under the command of the magistri or comites). Such a command could encompass a (part of a) province (styled after the name of that province, such as the dux Aegypti) or even several provinces (such as the dux Britanniarum (duke of the Britains), who commanded the regions straddled by Hadrian's Wall). Another name could be dux limitis, but these names were not standardised.
The dux ranked directly below the magister militum (but could appeal to the Emperor) and was responsible for the military protection of his own sector, including the military infrastructure, the collection and distribution of provisions and the military legal system. Valentinian I raised the duces from equestrian to senatorial status, which also reflects the ‘inflation’ of some military commands, which saw the replacement of several duces with comites during the fifth century. A dux received a salary of 1.582 nomismata (equalling 190 annonae and 158 capitus).


The tribunus (rank) was the commanding officer of a new-style unit, which could be a regiment of auxilia palatina or a numerus or anything in between. Tribuni of the scholae were commanded by the magister officiorum, but tribuni also commanded cavalry vexillationes, new-style auxilia regiments as well as the new-style legions of the field army, but also the old-style cohorts of the limitanei. By the mid-fifth century a tribunus might also be styled a comes, under the debasement of Roman military titles. By the sixth century a papyrus describes an old-style cohort commanded by a tribunus, eight senior officers including the adiutor (regimental clerk), the primicerius, six ordinarii and six others, probably the centuriones.
A so-called tribunus vacans was an officer temporarily without unit serving as a staff officer. These tribuni vacantes could also serve on special duties – when Ammianus was on a misssion from Ursicinus to relieve the magister peditum Silvanus of his command (read “arrest him”), he and his nine fellow domestici were accompanied by several tribuni vacantes. And in Egypt, a tribunus civitatis might combine military and civilian duties, acting like a governor. Tribuni could also be in charge of barbarian groups, as the example of the Tribunus gentis Marcomannorum shows. We know of one Agilo who was a tribunus stabuli in 357. These men (later comes stabuli) were responsible for gathering levies of horses for the army. A tribunus received 40 nomismata, 7.5 or probably eight annonae (plus four capitus if cavalry).

The praefectus (rank) was the officer in command of old-style legions (praefectus legionis) and of old-style alae (praefectus alae), although these were only to be found in the West, notably on the Danube and in Britain. Praefecti could also command several units together, as seen with the praefectus legionis quartaedecimae geminae militum liburnariorum cohortis quintae partis superior, Carnunto, who commanded the fourteenth legion as well as a part of the Danube fleet plus the fifth cohort, from his command post at Carnuntum.

The praepositus (post) was originally a title for any officer in temporary command of a unit, usually a vexillation on the way to or from a battle, later a classic numerus. This title could be held by officers of several ranks; prefects, tribunes or legionary centurions. In the Later Roman army, the praepositus was (like the comes) a name for a post, tribunes and prefects being addressed as praepositus or ‘officer-commanding’. Most of all we come across the praepositus as commander of old-style units, notably in the African provinces. Praepositi could command scholae units as well as old-style legions (praepositus legionis), old-style cohorts (praepositus cohortis), but there are also commands of less known units (praepositus militum, praepositus equitum and praepositus auxilia). Of course here, too, titles were used inconsistently, as is proven by the case of a prefect of an old-style ala (one Flavius Abinnaeus at Dionysias), who was also addressed with the title praepositus, and even as praefectus castrorum. In Africa, the limes was divided into sections, each commanded by a praepositus limitis subordinate to the dux. A praepositus could also command groups of laeti (praepositus laetorum), which were groups of barbarians who had been defeated in a campaign and settled throughout the empire under Roman supervision.

The protector (title) was originally a member of the select corps that Gallienus created as a group of loyal men around him. This group changed into a kind of school for officers, making men who were promoted from the ranks to become a protector before they were posted to their new ranks and duties. Some of these protectores were posted to the staff of field commanders (deputati) to gain experience, and performed a great number of duties. They could be sent to round up recruits and vagrants, or act as border guards controlling exported goods. Their more military duties could include the arrest of important persons, as related by Ammianus Marcellinus, who himself was a member of the ten protectores domestici in the staff of the general Ursicinus. This group was named domestici (men serving in the entourage of the Emperor, although also dispersed over the lower army staffs) to distinguish them from ordinary protectores, who succeeded to a command of a unit after serving for a number of years as protector. Other military tasks included special misssions, such as preparing temporary forts on campaign, or the arrest of officers.
When a soldier reached this stage of cadet officer, it finally meant a break from his original unit, because only the Emperor could decide to transfer men from one unit to another. Promotion was therefore very slow and it is not surprising that higher officers used their influence to get instant commissions for their sons. Bribery was rife in the Roman army, but men appointed thus instead of rising through the ranks had to pay certain fees and charges. When during the fifth century the flexibility of the promotion system decreased, the domestici and protectores became a static body.


The primicerius (rank) was the senior NCO (both in old-style as well in new-style units) whose name came first on the regimental muster-roll (matrix). A primicerius can be compared to a regimental lieutenant-commander, replacing an absent tribunus in the guise of the vicarius or as the tribune’s domesticus. Primicerii played an important role in the day-to-day administrative affairs. In the scholae they ranked as clarissimi, equal in standing to the tribunus, the next step in promotion. In unofficial sources the term becomes a generic description of any senior regimental officer. A primicerius received five annonae (plus two capitus if cavalry).

The vicarius (post) was the highest non-commissioned officer and could assume command in absence of a tribunus. He was not a strict rank but an ‘acting-tribune’, sometimes even from another unit. The formulaic coupling ‘vicarius vel tribunus’ from a number of sources signified the title of ‘commanding officer’ or ‘officer in charge’ regardless of his actual rank. When an infantry regiment was split into two equal parts, the tribunus commanded the first and the vicarius the second. Maurikios mentioned the ilarch (or the ‘senior hekatontarch’) for the case of a cavalry regiment, but see above. Vegetius mentioned a tribunis minor, which might signify a change in promotion procedured, or he might have had the vicarius in mind.

The domesticus (post) was a regimental chief-of-staff or adjutant. The term was also used in military and civilian life for a great number of assisting officers and officials with varying ranks. See also protector. Not to be confused with the select corps of domestici who accompanied the Emperor.

The campidoctor (rank) used to be as the regimental drill master or chief ‘training-officer’ of the Principate (before that and afterwards, a training officer was known as the exercicator or doctor armorum / armidoctor). Although it is still unclear if the roles and seniority of the campidoctor in old-style and new-style units were comparable, both Vegetius and Maurikios use the term for a regimental drill master. However, the campidoctor developed into one of the most important NCO’s, exclusive to the infantry. Ranking third behind the tribunus and the primicerius, and on occasion the campidoctor could (like the vicarius) take command of (part of) an infantry unit.
According to Maurikios, the campidoctores accompanied the tribunus before the engagement, before taking their place besides the standard in battle. Vegetius as well as Ammianus associated the campidoctores with the classical antesignani (in a non-technical classicising manner), signifying that they fought in the front rank.

The senator (rank) served in several troop types including the scholae, but otherwise nothing is known about this rank. A senator received probably four annonae (plus two capitus if cavalry).

The ducenarius (rank) originally was a class of minor judges who sat in minor cases (Suetonius, In Augustum, cap. XXXII). There was also a civilian ­procurator ducenarius. Not much is known of the Late Roman ducenarius, although he may have commanded two hundred men, which would be logical if the new-style campidoctor commanded part of a unit. However, this may be due to a misunderstanding of Vegetius, who mentioned this rank as a rank between the centurion and the primus pilus of his theoretical ‘Legio Antiqua’. Vegetius was in all probability wrongly equating ‘ducenti’ into ‘ducentenarius’. A classic example of a ‘ducentenarios’ however is not known from the military, but from horse-racing, as a horse with two hundred victories (Diocles). As a result we cannot be sure if Vegetius, as he often did, made something up or mentioned the actual number of men under the command of a ducenarius. The word ‘ducentenarius’ as a commander of two hundred men is not known before Bede (8th c.). A ducenarius received three-and-a-half annonae (plus one-and-a-half capitus if cavalry).

The centenarius (rank) likewise seems clear-cut as a commander of a hundred men, but although Vegetius compares them to centuriones (maybe just by etymology), it’s by no means sure that the name refers to the number under his command. Lucius Artorius Castus was a procurator centenarius of Liburnia. The second-century title procurator centenarius may have referred to his salary, and the Late Roman centenarius portus (a unique command mentioned for the city of Rome) seems too important to be ‘just’ a centurion. Maybe it’s not surprising that, like the ducenarius, the centenarius was also originally a legal function. A centenarius received two-and-a-half annonae (plus one capitus if cavalry).

The ordinarius (rank) seems to have been the same as the centurion of the old-style regiments, commanding eighty men according to a papyrus describing a sixth-century cohort. Odd enough, the ordinarius, although widely attested, does not appear in either Jerome's or Justinian's list, so perhaps

The biarchus (rank) seems to have been a junior officer comparable to the decuriones which continued to exist in old-style units and who commanded an eight-man strong contubernium. The word biarchus literally means “in charge of the food supply”, or “mess-leader” or caput contubernium, which may indeed point to his practical role in commanding a contubernium.
Vegetius refers to this rank as the decanus, comparable to Maurikios’ dekarch, which means “set over ten” or “commander of ten”. Both may well have been purely theoretical though (comparable to a centurio commanding 80 men instead of a 100), instead of signifying a real change of the contubernium from eight to ten men.
The first example known of a biarchus is from a tombstone from Concordia of a biarchus draconarius. This Flavius Iovianus, serving in a late fourth-century vexillation of the Octavodalmatae, was therefore probably the file-leader as well as the draconarius. The optio draconarius may refer to a similar combination. A biarchus received two annonae (plus one capitus if cavalry).

The circitor (grade) was the lowest NCO grade. According to Vegetius, the circitor was once a post of the inspector of the sentries, but evolved into a rank of which we know little to nothing. A law of Constantine stipulated that sons of cavalrymen could, provided he brought two horses or a horse and a slave, start immediately as circitor. A circitor received two annonae (plus one capitus if cavalry).


The semissalis (grade) may have been a senior soldier with higher pay, receiving one and a half annonae (plus one capitus if cavalry).

The pedes and the eques (rank) were the common privates of the infantry and the cavalry. A pedes may have received one annona, and an eques may have received one annona plus one capitus.

The tiro or recruit was the lowest rank in the army, which a man held from joining during his training period. During this time he did not receive full pay and allowances. An advice to Valens and Valentinian entailed keeping groups of between fifty and a hundred tirones attached to each unit, admitting them upon vacancies. A tiro may have received a half annona (plus one capitus if cavalry).



  • Notitia Dignitatum, In partibus Occidentis, in partibus Orientis, full text (Latin) at: http://www.thelatinlibrary.com/notitia.html.
  • Maurikios: Strategikon, Handbook of Byzantine Military Strategy, trans. by George T. Dennis, (Philadelphia 1984).
  • Vegetius: Epitome of Military Science, trans. N.P. Milner, translated texts for historians vol. 16. (Liverpool 2001).

Secondary literature

  • Jones, A.H.M. (1964): The Later Roman Empire, 284-602, A Social, Economic and Administrative Survey, 2 vols. (Oxford paperback 1990).
  • Rance, Philip (2007): Campidoctores Vicarii vel Tribuni: The Senior Regimental Officers of the Late Roman Army and the Rise of the Campidoctor, in: Ariel S. Lewin and Pietra Pellegrini (eds.) (2007): The Late Roman Army in the Near East from Diocletian to the Arab Conquest, pp. 395-409.
  • Southern, Pat and Karen Dixon (1996): The Late Roman Army, (Routledge).
  • Speidel, Michael P. (2000): Who Fought in the Front?, in: Géza Alföldy, Brian Dobson, Werner Eck (eds.): Kaiser, Heer und Gesellschaft in der Römischen Kaiserzeit. Gedenkschrift für Eric Birley (HABES 31), (Stuttgart) 2000, pp. 473-82.
  • Treadgold, Warren T. (1995): Byzantium and Its Army, 284-1081, (Stanford University Press).

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