Late Roman Unit Sizes

[Timus]

Do you think there is any mileage in the suggestion that if Ammianus gave two clear examples of detachments numbering 300 men each were taken from the parent unit then this was a standard detachment size at the time Ammianus served in the Late Roman Army?

Possibly. Although Amm also mentions detachments of 500 on a couple of occasions, and a thousand at least once.

Regarding the possible habit of detaching 300 men from a given legion, I can't help but think of this 2 passages from Caesar BA 75:

 But this contingency had not escaped Caesar's attention: he had in fact given instruction that three hundred men out of each legion should be in light order; and these he accordingly disestablished against Labienus' cavalry to give support to his own squadrons.

Quae res Caesarem non fefellerat: namque expeditos ex singulis legionibus trecenos milites esse iusserat.

and BA 78 :

When Caesar observed these tactics he instructed the three hundred men in light order — it was his normal practice that this number of men in each of his legions should be in light order — from the legion which was posted in the line nearest the scene of this action to hasten to the assistance of the cavalry. 

Quod ubi Caesar animadvertit, CCC, quos ex legionibus habere expeditos consuerat, ex legione quae proxima ei proelio in acie constiterat iubet equitatui succurrere.

http://penelope.uchicago.edu/Thayer/E/Ro...ar/D*.html

Somebody with only a basic knowledge of the organization of a roman legion would expect a lot of numbers but not 300. Something like 60, 80, 120, 160, 480, 500, 800, 1000 would make sense but 300... ? So what are we missing ? Was there a long standing rule (from Caesar all the way to Ammianus !) of creating a legionary detachment of 300 men ? Is it just a coincidence ? Why mentioning a specific number of men rather than a specific unit level (century, maniple, cohort) ?

[Flavivs Aetivs]

300 men is clearly a rounded figure.

[Steven James]

Evan wrote:

300 men is clearly a rounded figure.
 
It would depend on the sub organisation. If it was composed of five centuries each of 60 men, then it is not a rounded number. If people on this forum continue to ignore the concept that the Roman army still functioned on cohorts, maniples and centuries, then you will continue to be bricked in.
 
I forgot to mention that in the example of Zosimus and Sozemen relating to the force of about 4,000 men or 40,000 men, Zosimus has six tagmata amounting to 4 myriads. So 6 units to 4 units produces the ratio 3:2. That is another mathematical key to understanding why Zosimus ends up with 40,000 men.

[Marcel Frederik Schwarze]

I am afraid the only mathematical formula in ancient greek and roman warfare is to get a [...] σύμμετρος στρατός [...] - a symmetrical army.
Asklepiodotus II 1. + ibid VI 3.

This slogan or motto is also repeated by many other roman tacticians and military historians. Even the roman Αὔγουστος Mauricius informs us many centuries later:
[...] We need a symmetrical army if we want be the master of the enemy - however a bigger one [means: an army more huge is needed), if we want get control (φυλάττειν) about the land conquered from the enemy [...]
Strategicon VIII 2, 84

Completely without illusion and mathematical learning, Mauricius must calculate pragmatically with the troops at his disposal. With Roman stubbornness and serenity he goes on to explain that most of the troops have a different size. Therefore, Mauricius say, a way must be found to squeeze these regiments [αριθμοι] into a uniform scheme on the battlefield.
Here he again recalling the Greek military theory of symmetric warfare.
The troops arriving on the battlefield must stand side by side in their λοχοι (files/contubernia) - always 8 deep - or if 2 files fought togehter 16 deep. One file is called as primani, the other one as secundi. Always 2 files are bonded together. The leader of the first file is called decanus or decarchus, the second file leader is the lochagus (and obviously inferior as secundi compared to the primani).

All files were placed side by side - forming ad-hoc tagmata. This is a battle field module, a brick, an element temporarily created for this battle. Important here is that all 4 parts of the Mere (is composed by several tagmata) have [nealry] the same size. If a regiment is too big, he suggest to divide this αριθμος to create 2 tagmata. The first Tagma stays with the tribunus, the other one with the campiductor.
It is suggested today that the latter one could be
a) the first of the κεντυριονες for a classical old unit, following the old internal order or
b) in case of a unit following a new order it was probably the senior κεντεναριος (this was the senator)
c) the tribunus minor or primicerius (if available like in the case of the "legion" at Perge) is most likely for nearly all units a valid option.

The whole procedure was not just done to harmonize the battle formation on the day of the battle, but also to harmonize the ad hoc ranks and titles at this day was an important step to keep the communication and to promote/keep sensitivity between all the different troops.

And some last words regarding the Bandus and Numerus. I think that I told that once in one of my older posts, a Numerus (new-numerus, old legion ect) was of course subdivided by centuriae, since their leaders were evidently centuriones or centenarii. These, in turn, were divided into files/lochoi/contuberni of 7 or 8 soldiers. Cautiously one can say that there are indications that some regiments put 10 soldiers in a tent - namely armaturae (light psiloi, auxilaries) - also described in the Strategicon.

To my moddest knowledge it is not before the editing of the Praecepta Militaria of Nikephoros II Phokas that small banda of 50 mounted men each are composing a single tagma/numerus. I have to check this source once more. Even if I personally find all information worth reading, but here I'm not sure if a book written in 965 AD can deliver important details regarding the deployment of units in 480-580AD. Anyway, an interesting note is that the Arithmos can be observed until the Theme-organization broke down - but I'm sure that we find a similar graeco-roman regimental system also after 1204 AD. But that's another issue - and may be discussed by other people.

The Strategicon makes a clear distinction between banda and numeri - those terms were translated and to my disapproval mingled by G.T.Dennis in his book, which leads always to the same discussions.
In this case I have to translate an importan key-sentence by myself:
Strategicon I 3, 14-15: The moira however consists (out) of tagmata, truly (namely) composed (or formed) by the Numerus or Bandus.
[...] μοἰρα δὲ τὸ ὲκ ταγμάτων ἤτοι ὰρἰθμῶν ἤ βάνδων συγκείμενον πλῆθος [...]

I also enjoyed the last discussion regarding the terminus numerus. I miss a little bit the factor "time" in the evaluation of this topic. The Roman army stood in a process of changing circumstances.
I think it is important to take a closer look at the old barbarian numeri. Today we know that some of those numeri were created out of the old ethnic troops, just called gentiles or gentes. For a short time some of them got a new designation (called vexillatio) - followed after some years by the term "numerus". Some of those numeri were later promoted to an alae or cohors - some of the old numeri provided both kind of troops - which shows once more the procedure of promotion of whole units!

The term "numerus" was a colloquial expression at the beginning of the time period in question for all units. Somewhere during the 4th century the term get more and more access into official military documents, first time confirmed by some paragraphs in the Codex Theodosianus, and closed up in a broader sense by the Notitia Dignitatum. During that time however all units still kept their identity. In the next years until the time of Heraclius we find papyri calling the old units "numerus legionum" (αριθμος τον λεγεονων) or "numerus coortis".
The numerus became the technical description of the regiment, the second part was after ~460-480AD a classizing epitheton. It was part of tradition and proudness. Furthermore papyri show very clear that old ranks and titles were kept as well in those units (e.g. ορδιναριος or κεντυριον).

That old terms like legio, ala, cohors etc. were still known in the official military language in the 6th century is also well known by reading the Codex Iust. Just tell if sources are whished. But they are so numerous that I would now refrain from doing so. But those terms were outdated and had no (or at least no noteworthy) meaning anymore.

So, and now we come to the question about new deployed units. They were just called "numerus" because the generic official technical term for all regiments in the empire (old+new) was the numerus. It was shifted from a colloquial term to an official technical term, a procedure at the lastest esablished round about 470AD. The numerus was the only term for infantry. Exceptions were the scholae and for cavalry it was acc. the Strategicon the bandum (flag or banner). All those new deployed numeri got of course an additional name of the city where they were deployed or they got the name of the ruling emperor or his sons.
Numerus Mediolanensium, Numerus Genuensium, Numerus Iustinianus .....
Concerning the new-numeri I agree that a kind of a certain equality was aimed. There are indicators and sources suggesting a number between 500 and 530 men for infantry during the time of Justinian and later on - which is no surprise since that number fits the old cohorts. But this must remain speculative. Other new units had probably 800 men, or just 200... who knows.

But it is a fact that old and new units lived and fought side by side with their own internal hierarchy. And I can imagine very well what happened to Maurice when he saw the first time this colorful bunch on the battlefield. In some regiments the soldiers were speaking coptic, others vulgarlatin, another group a kind of thracian dialect, the rest was speaking greek... not speaking about the countless regiments of armenians and syrians. On the day of a field battle some units arrived with 1500 men, others with 120 men only. Of course there was a need to harmonize all this differences and to declare once more "latin" as the only valid language for all military units and due to the harmonized file-structure we find a tribune or a campiductor in the middle of all ad hoc tagamta. Small units provided 10 files to the right and 10 files to the left of the tribune. Bigger units provided 20 files to the left and 20 to the right (or even more). But for the enemy it was an equal looking "wall" and this system removes inequalities in the strengths of the regiments concerning the manpower.

[Flavivs Aetivs]

Campidoctor was certainly not the Senior Centurion since that title had been around since the Principate, at least.

Otherwise, excellent post.

[Nathan Ross]

In the next years until the time of Heraclius we find papyri calling the old units "numerus legionum" (αριθμος τον λεγεονων) or "numerus coortis".

Aha, fantastic! I've been wondering for a while whether such a term might have existed - I guessed something like numerus legionis - but even if it wasn't used earlier (because unnecessary?) it proves that the late Romans could and did distinuish between different types of numeri. Perhaps we could also assume the existence of a numerus auxilium, besides the numerus equitum mentioned in the inscription I quoted before?

I can imagine very well what happened to Maurice when he saw the first time this colorful bunch on the battlefield.

I'm sure! Is it not possible, in fact, that a military manual written by an emperor would not be intended merely to record a current situation, but rather to lay down some principles of reorganisation? So the Strategikon would act as a plan for a future army, rather than a picture of the current one.

Campidoctor was certainly not the Senior Centurion since that title had been around since the Principate, at least.

It had, although the meaning seems to have altered. Far from being only 'drill instructors', as before, the later campidoctores seem to have been among the most senior officers in the legion, leading attacks and even crowning emperors.

Perhaps the introduction of ordinarius as a new title for centurions might obscure the fact that the campidoctores were centurions too - the most senior, perhaps, similar to the old primi ordines, or even the praefectus castrorum and primus pilus?

I should probably have another read through Rance's essay on the subject...

[Flavivs Aetivs]

IIRC it seems that the Campidoctor went from being a drillmaster to a quartermaster and then the chief of legion paperwork, likely including pay.

[Nathan Ross]

to a quartermaster and then the chief of legion paperwork, likely including pay.

I don't think so - aren't you thinking of the actuarius or adiutor? The campidoctores were fighting men - those of the Gallic legions led the sally during the siege of Amida, and were later commemorated by statues in full armour at Edessa. Campidoctores are often mentioned among the principal officers of the legion, and appear in crowning ceremonies of later emperors, including Leo and I think Anastasius. They were certainly not mere chief clerks or quartermasters! They were either very senior veteran soldiers or a grade of centurion/ordinarius.

[Flavivs Aetivs]

Eh I'd have to check Fectio again, Robert has their roles in the late Roman legion up on there.

[Timus]

Regarding the campidoctores, for reference:
https://www.academia.edu/3677107/_Campid...07_395-409

[Marcel Frederik Schwarze]

In the next years until the time of Heraclius we find papyri calling the old units "numerus legionum" (αριθμος τον λεγεονων) or "numerus coortis".

Aha, fantastic! I've been wondering for a while whether such a term might have existed - I guessed something like numerus legionis - but even if it wasn't used earlier (because unnecessary?) it proves that the late Romans could and did distinuish between different types of numeri. Perhaps we could also assume the existence of a numerus auxilium, besides the numerus equitum mentioned in the inscription I quoted before?

Hi Nathan,
I put another one on top :-)
the numerus vexillationis Ombos
P.Laur. 3 111, Antinoopolis, 575-599 AD: ἀριθμοῦ οὐιξιλλατίονος Ὄμβων

And yet. After looking at all the evidence, this term appears to have only a traditional meaning like all the others. It cannot otherwise be explained that all new numeri were "only" called numeri (+cityname or name of the emperor or name of the tribe).
All the new numeri deployed by Justinian (especially in Egypt and the Pentapolis), or by Tiberius (and his Tiberiaci) etc. were set up as numeri only without additional term like legio, cohors, auxilia. If those designations were still valid (to a certain degree) I would expect at least some new legions - which is not the case. Especially Justinian was very backward looking.

I do not reject a superior position of an old legion in a 6th century field battle.
But it has probably different reasons. I strongly believe that these ancient legions maintained a high degree of discipline, I still believe that special formations were practiced, and Papyri show clearly that the internal order was still strictly oriented to the past - which is in my opinion no disadvantage. To this extent, the old legions may indeed have provided an interesting offer for a military campaign and its commander.

But according the Notitia Dignitatum the "flower" of the army was the auxilia palatina. In all lists, they are named first. The reasons are debatable, and not my point now.
But meanwhile (late 5th + 6th century), they are also completely integrated into the structure of the numeri.And much more. The term Auxilia has completely disappeared.

P.Paramone 15, 592–593 AD: ἀριθμῷ τῶν καθωσιωμένων Θεοδοσιακῶν Ἰ̣σαύρων (only an arithmos)
= Felices Theodosiaci Isauri in Alexandria, acc. ND Or. V 25 and 66 an auxilia Palatina serving under the MMP1

We know many names of officers and recruits in Egypt of former auxiliae in the late 5th and 6th centuries. All have Roman or Graeco-Roman names - and were mostly locally recruited . In this case the old difference on a cultural basis no longer exists. That an old Auxilia unit maintained certain traditions is probable. But are these so comprehensive?
Mommsen and Robert Grosse explained that the catastrophic events in the West were an important indication and warning signal to the Eastern Empire. On top of that there was the Civil War with the Isaurians under Anastasius. Was this a reason for the Romanization of the old auxilia and other troops or for reducing foreigners in the army in general? Or does it have something to do with the fact that units have been stationed in one place for a long time, and reinforcements were added by Romans - a stepwise procedure so to speak? Who knows...

The fact remains that the name "auxilia" was taken from this units.
Proc. de bellis 5,23,3: οἱ Ῥῆγες ἐνταῦθα, πεζικὸν τέλος, ἐφύλασσον καὶ Οὐρσικῖνος, ὃς αὐτῶν ἦρχε
just named Reges (Regii, an aux. palatinum)

P. Ital.16 +/-600AD, Ravenna: Iohanni viri clarissimi, primicerii numerii felicum Theodosiaci
probably Aux. Pal. see ND Or. V 62 serving under the MMP2: Felices Theodosiani

CIL V 8280, early 6th century: de num(ero) Zal(iorum) qui bixit annis
Zal(iorum) = Saliorum? = Salii. compare ND Or. V 51 auxilia pal. serving under the MMP1

[...]

Beside the drungus/globus (an undefined small tactical body) and the scholae, the only tactical units which can be observed beside the numeri are the ιλαις ιππεων (alae equites) - the latter one just in ancient literature e.g.
Evagrius, Hist. eccl. V 15: ἑκατὸν χιλιάδων ἴλας ἱππέων ἀρίστων ἐγκαταστήσασθαι

Within the century turn (5th to 6th) there is an interesting inscription in Tomis.
SEG 28, 626: σαγιτταρίον τῖς τῆς ειʹ [ιεʹ] πολεμαρχικῆς [πολεμικῆς] ἴλης.  
An ala of sagittarii

Some years before in AE 1976, 0617 (also Tomis): filius Gaion(a?)e annor(um) viginti cinque militans inter sagittar(io)s iuniores
...without any ala or something else.

Possible that the term ἴλη is interchangeable with ἱππέων (equites in the meaning of cavalry in general) or a cavalry-bandum (βανδων). Perhaps the Ala has indeed survived. I mean I can find a lot of those 6th-century alae. But a general pattern is not visible at the moment.

[Nathan Ross]

All the new numeri deployed by Justinian... were set up as numeri only without additional term like legio, cohors, auxilia.

Does it seem likely that by the 5th-6th century the distinctions between the units had been largely erased? Older units may have hung on to their titles as 'legions' or 'auxilia' for tradition and esprit de corps, despite the lack of practical difference, while newer ones lacked them entirely?

Proc. de bellis 5,23,3: οἱ Ῥῆγες ἐνταῦθα, πεζικὸν τέλος, ἐφύλασσον καὶ Οὐρσικῖνος, ὃς αὐτῶν ἦρχε
just named Reges (Regii, an aux. palatinum)

Doesn't the ND lists the Regii as a comitatenses legion? Speidel suggested that they (as auxilia) were based on the retinue of King 'Crocus', who apparently joined Constantius I in AD306. It seems maybe more likely that they were related to the numero Regiorum Emesenorum Iudaeorum that appear at Concordia (CIL 05, 08764), in which case perhaps their unusual 'eastern' origin may have caused an early blurring of the distinction between auxilia and legion?

I suspect we could think of the auxilia palatina as being something like the 'foreign legions' of France and Spain - elite units, raised initially from foreigners but increasingly composed of non-foreigners. Although we should remember Ammianus's description (31.13.8) of the Batavi at Adrianople as adventicio (foreign).

[Marcel Frederik Schwarze]

All the new numeri deployed by Justinian... were set up as numeri only without additional term like legio, cohors, auxilia.

Does it seem likely that by the 5th-6th century the distinctions between the units had been largely erased? Older units may have hung on to their titles as 'legions' or 'auxilia' for tradition and esprit de corps, despite the lack of practical difference, while newer ones lacked them entirely?

Yes, I think so. However with a small objection.
If the course of the day corresponded approximately to earlier times, then the soldiers of the old legions may still have had a better training.
The Roman drill and the labor service were very unpopular within the auxilia.
Amm. XVIII 2,6 & Veg. II 3 (at the end of the text)

On the other hand, only Romans served in the former auxiliaries in the late 5th and 6th century. Thus, there is probably no difference anymore between the numerus legionum, former auxilia palatina and new numeri.

If old procedures were still valid and respected by keeping the tradition e.g morning roll call, fencing, practicing formations, then there was maybe a small difference compared to other units. But this remains pure speculation from my side. For a long time it was believed that many soldiers in Egypt pursued a second profession.
In particular, the Papyri show that this was not the case.
So I still have some hope for our old legions.

Proc. de bellis 5,23,3: οἱ Ῥῆγες ἐνταῦθα, πεζικὸν τέλος, ἐφύλασσον καὶ Οὐρσικῖνος, ὃς αὐτῶν ἦρχε
just named Reges (Regii, an aux. palatinum)

Doesn't the ND lists the Regii as a comitatenses legion? Speidel suggested that they (as auxilia) were based on the retinue of King 'Crocus', who apparently joined Constantius I in AD306. It seems maybe more likely that they were related to the numero Regiorum Emesenorum Iudaeorum that appear at Concordia (CIL 05, 08764), in which case perhaps their unusual 'eastern' origin may have caused an early blurring of the distinction between auxilia and legion?

You could be right here.
Strictly watching at the ND the unit appears as legio in the west (Occ. V 229) and as an auxilium in the east (Or. VI 49).
Perhaps a detachment of the legion has been promoted to an auxilium? But I will take a closer look regarding the retinue of Crocus.

This reminds me of another thing in the context of my research. Ammianus calles the Iovii and Victores a legion.
(ibid XXV 6,3)
But acc. the Notitia the Iovii and Victores (iuinores, seniores etc) were all classified as auxilia palatina.

It has long time been claimed that Ammianus is wrong here.
Meanwhile, I think he knew very well what the Iovii and Victores were. Perhaps another indication for a promotion from legio to an auxilium palatinum within the decades between 360 and 420 AD.

I suspect we could think of the auxilia palatina as being something like the 'foreign legions' of France and Spain - elite units, raised initially from foreigners but increasingly composed of non-foreigners. Although we should remember Ammianus's description (31.13.8) of the Batavi at Adrianople as adventicio (foreign).

I think that most of the aux. pal. during the military service of Ammianus were still composed by foreigers. In the west perhaps far into the fifth century as well.

[Nathan Ross]

I will take a closer look regarding the retinue of Crocus.

You can read Speidel's paper here. I notice he discusses the 'emesenorum iudaeorum' inscription and dismisses the reading - rather convincingly I have to say! However, if the Regii dated back to Constantius I I would have thought they would be further up the hierarchy of units. There were surely other 'kings' they could have been named after - even if we needed an actual king. Many auxilia units seem to have had rather 'symbolic' titles.

I think that most of the aux. pal. during the military service of Ammianus were still composed by foreigers

Yes - many of the Concordia inscriptions record men in aux units with 'barbarian' names. Although (as I think I've said before) our only recorded origin for an auxilia soldier claims the man was born in Singidunum!

But we should return to the topic of unit sizes, perhaps...

Ammianus calles the Iovii and Victores a legion.

Is there any support in 5th-6th C sources for this 'doubling' of units? It seems very common in the 4th century, especially with auxilia numeri.

If we follow the idea that the 'numerus legionum' (if you'll pardon the anachronism) might originally have been based on a two-cohort legion vexillation, as we see in the tetrarchic II Herculia inscription from Mauretania, and other places, might a 'numerus auxilium' have originally have been half the size, i.e. around the strength of an old cohort, and this is why they seem so often to operate in pairs?

---

300 men is clearly a rounded figure.

Not necessarily - if the writers wanted to say four centuries or half a cohort or whatever then they surely could have done so?

three hundred men in light order — it was his normal practice that this number of men in each of his legions should be in light order — from the legion

300 does seem quite common. But I notice that Ammianus has Julian also equipping '300 light armed men' - this might mean that it was a common practice, or perhaps that Julian (with his interest in military antiquarianism) had read Caesar and was deliberately emulating him!

[Flavivs Aetivs]

Is there any support in 5th-6th C sources for this 'doubling' of units?

No, unless there is a papyrus or tombstone I am unaware of. The period from 410-490 is effectively a dark age for Roman military inscriptions, artefacts, Roman literature, Roman art... pretty much everything.

One could make a slight argument though for this in Claudian's description of the units deployed for the Gildonic war in Africa.