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Late Roman Unit Sizes
(10-16-2018, 06:37 PM)Flavivs Aetivs Wrote: Two cohorts, each 6 centuries.

Ah, right.

Jones (LRE 2, pp681-682) reached his estimate of 3000 men for 'the rumps of the frontier legions' by assuming that each had two 1000-man (ie two cohort) vexillations drawn from it, which had turned into field army units at a subsequent point. That would make 960 men a better estimate for the comitatensis legions... although Zosimus's figure would suggest 1200...

If we took one of the estimated sizes for the so-called 'Perge legion' (1172 plus 300 cavalry), this could round up to about 1200 men, or 1500 with additional mounted troops, which might fit one of those Lejjun/Udrah/Palmyra/Boppard - sized fortresses quite well.

Meanwhile, I was looking for other late fortresses with excavated barracks or internal buildings and came across these three smaller forts:

   

All three, I think, are Diocletianic or thereabouts. El-Kab appears to have six barrack rooms in one range and three more along each side, with perhaps another pair of three rooms each at the bottom - either 12 or 18 rooms total. By size (only 0.2 hectares) this fort should house 60 men by principiate men-per-hectare standards. That would put either three or six men in each room, assuming each room was a barrack. Alternatively, with more men per room the garrison could have been larger.

Khan al Hallabat in Syria is a similar size (0.22 hectares), and was probably the Veriaraca of the ND, making it the base of the Ala Nova Diocletiana. Qasr Bashir in Jordan was only slightly larger, and had stabling for up to c.69 horses.

Abu Sha'ar (Aby Sha'ar on the plan above) is 0.5 hectares, but held 54 barrack rooms in nine groups of six, plus additional rooms around the walls. By area it could have held 150 men - but that would only be 2-3 men per room. Perhaps the men were sharing their rooms with additional 'family members', or some of the rooms were used for other purposes? Alternatively, with a full eight men per barrack room we would have 432 men in the garrison.

Dionysias fort in Egypt is 0.75 hectares, large enough to house 225 men. But again we have around the same number of barrack rooms (53 this time, it looks like), and once again they are divided, more or less, into groups of six. Four or five men in each room would make up the garrison strength. Alternatively, the garrison could have been the same size as the one at Abu Sha'ar...

So once again the results are fairly inconclusive, except to underline the relatively small sizes of late Roman frontier units: 60 or so men for an ala, perhaps. Maybe a late ala was the size of two old-style turmae, just as a legion (in some cases) was the size of two old-style cohorts? This might be disproved by the multiplication of ranks on Egyptian papyri, of course: some of the alae appear to feature numerous decurions. These plans also seem to indicate a subunit size divisible by six.
Nathan Ross
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There's no way a standard Ala could be 60 men. The ratio of infantry to cavalry in the army would be incredibly skewed. Over 95% of the army would be infantry, at least.

I think many of these forts were detachments of units, with others in nearby towns and cities. Don't forget, the de metatis law points out that Roman troops were quartered in houses too, not just forts.
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(10-17-2018, 01:59 PM)Flavivs Aetivs Wrote: I think many of these forts were detachments of units

That's possible, although all three of the forts above have a Principia, and two have praetoriums, which would suggest a complete unit, or at least the headquarters of one. Most of them are in fairly rural or thinly inhabited areas too; we'd have to assume large numbers of troops spread around the surrounding area, quartered in villages or endlessly patrolling and only returning to base on rotation, perhaps...

The eastern ND lists a number of alae and cohortes de minore laterculo; while most of the garrison sites are unidentified, they are probably mostly small forts like Khan al Hallabat, or El Kab. Perhaps this 'lesser list' comprises a lot of much-reduced old units now relegated to local policing or frontier patrolling? The numeri equitum of the main list would be the 'real' cavalry force.

As for the ratios of troops - the frontier infantry would be perhaps be in units of a similar size.
Nathan Ross
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From Luttwak's The Grand Strategy of the Roman Empire: following the II century, the Roman Fortresses chnged their size and organization, here an example:
[Image: 2nd-century1.jpg?w=500&h=237]
[Image: late-3rd-century.jpg]
[Image: late-4th-century.jpg]
In some cases, the fortresses were build inside previous forts (Vindonissa, Eining). It is not really easy to estimate the number of men of a fortress of the late period, comparing it to to the number of men of a fortress of the second century.
- CaesarAugustus
www.romanempire.cloud
(Marco Parente)
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(10-29-2018, 08:06 PM)CaesarAugustus Wrote: the Roman Fortresses chnged their size and organization, here an example

Thanks! That's an interesting contrast. However, aside from the external defences, it looks like the main change between the Antonine and Diocletianic era forts was in the number of barrack blocks, and the size and number of the rooms within blocks: the later 3rd century fort appears to have fewer but much larger rooms on the same 'footprint' as the earlier- style fort. This might indeed have something to tell us about changes in unit size or internal structure (larger contubernia? smaller centuries?) - but unfortunately interpreting the changes is none too easy!


(10-29-2018, 08:06 PM)CaesarAugustus Wrote: It is not really easy to estimate the number of men of a fortress of the late period, comparing it to to the number of men of a fortress of the second century.

I'm not so sure. The example given for the late fourth century is indeed very irregular, but we have examples from the Diocletianic era that also appear like this.

However, there are also fortifications from the 4th century onward that are quite regular quadrilaterals (Boppard, Deutz, Udrah, etc), and where we have remains of barracks blocks they seem to follow a similar sort of plan to the earlier forts and fortresses. So unless the later Romans were using a totally different method of accommodating troops in fortresses (two-storey blocks? Massive out-stationing or local billeting? Some sort of 'hot bunking'?) we ought to be able to use the numbers from earlier eras to estimate later numbers too. Although, as I've come to see from my various rough attempts at calculations, this isn't that simple either...
Nathan Ross
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It is probable that in that places not on the border or near the border there was not the necessity to maximize the defensive capabilities, while near the borders the fortresses where subject to the necessity to maximize the number of men in a smaller space.
- CaesarAugustus
www.romanempire.cloud
(Marco Parente)
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It's important to remember that Luttwark's thesis was at best wrong, though.
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Yes and no, some ideas are interesting and challenging. Also, some of the confutations I read about his work are irrelevant and probably wrong.
- CaesarAugustus
www.romanempire.cloud
(Marco Parente)
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https://www.academia.edu/37743639/The_Le...man_Period
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I’ve just finished the chapter on the Late Roman legion. It was to say the least, a mathematical conundrum of the greatest proportions. I feel I have for the last two weeks been fighting in the trenches on the Somme.

 
Understanding the Roman tribal system has made remarkable discoveries, but when it came to the Late Roman legion, it only partially could interpret the unit sizes (50%) in the primary sources. It was a bit of a body blow to come so far and fall just short at the end.
 
I finally located the problem. It was my preconceived concept of the Late Roman legion that was the road block. I was fixated the legion had to be small. So I approached the problem differently and after examining the data for the 35 tribes that would cover the Late Roman legion time frame, it all started to fall into place. Besides the standard practice of making detachments during the republic and principate, the Romans had introduced a new system of forming detachments from legions. So two systems of forming detachments in play. I felt it was akin to the German U boats during WWII introducing a fourth wheel to their enigma machine.
 
The actual Late Roman legion is large. The legion has both iuniores and seniores organised into vexillations, cohorts, maniples, centuries and cuneii. After removing some units (in the same manner as the triarii in the old days), a smaller legion exist made up of iuniores and seniores. The sizes of the standard units will change.
 
So two legion sizes containing iuniores and seniores. The Romans can also take the full strength legion of iuniores and seniores and they remove the seniores. All organisations within the legion change in size. Then further detachments are made. This system can produce four legion sizes of iuniores. This mean six legion sizes in play and that is why the variations in numbers.
 
I’ve done all the organisation diagrams of all six legions, and then took all the data I could find on the legion for this period so as to determine which legion they belong to. I have found the legion size and organisation which relates to the 1,500 lancerii and the mattiarii. Three units of 500 men. No rounding. A perfect match. This one has eluded me before and been a thorn in my side.
 
Ammianus seven legions and a number of numerii amounting to 20,000 men at Amida had revealed more insights into the Roman military. Whatever sizes the legions were and how they were organised, the numeri with them has the same organisation. This makes sense because if the units had to deploy for battle in a field, they would have to be compatible. Imagine in the republic putting four legions in the field with one missing the triarii, another missing the antesignani, another missing both the antesignani and the triarii. The Romans are very pragmatic, and the number of men I have is extremely close to Ammianus’ 20,000 men.
 
Some people here don’t have much regard for the Christian martyrs, but Saint Meletius reference to 252 soldiers is also a perfect match. Another perfect match, which means no rounding but on is spot on. Another perfect match is Macarius of 1,104 soldiers were stationed at Melitene. It contains both infantry and cavalry and accurately conforms to one of the six legion organizations I have.
 
The force of Mascezel to suppress a revolt from Gildo as detailed by Claudian and the force given at 5,000 by Orosius also conforms. Glaudian’s use of the term cohort is correct. The 400 men in ambush at the Baths of Zeuxippos is correct. All unit number, both infantry and cavalry in Ammianus, John Lydus, Zosimus and Sozomen etc have now given up their secrets. But the biggest prize is in “The Acts of the Disputation of Archelaus,” which mentions that 7,700 Christians were taken prisoner, 500 wounded and 1,300 killed, are, as I have claimed before, taken from a military garrison force. I found what organisation they are adhering to and the rounding of the numbers is within point 001 percent. Yes I am aware the Second Book of Chronicles also uses the number 7,700 for the size of a flock of rams and goats. And our author knew this and purposely portioned the Roman military organisation to reflect this as he must have seen the similarity.
 
The cavalry squadrons also change in size when the seniores are removed. The instigator of these military changes was Diocletian and the evidence to support this collaborated from many sources.
 
In summary, there is nothing wrong with the numbers in the primary sources. Finding out how Roman military doctrine works is the key to understanding the numbers. Introducing a second system of detaching troops was the new doctrine. It has been a journey.
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Rufinus Latin translation of Eusebius Ecclesiastical History 5,5,1 states that a Roman Legion had 6000 soldiers.

https://archive.org/details/corpusglossa...t/page/104
*
Like Jerome...Wait, what happened to the “References to late Roman army???” thread?!
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(03-12-2019, 11:05 PM)Julian de Vries Wrote: Eusebius Ecclesiastical History 5,5,1

That passage is about the 'rain miracle' and Legio XII during the Marcomannic Wars; it's quite probable that a legion of that period did indeed number 6000 men, officially at least.
Nathan Ross
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Is it not more - if not at least equally - likely that someone multiplies 60 x Centurions/Centuries by 100 to get 6,000.

Josephus, writing much earlier, certainly seems to do that with his auxiliary cohorts...
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(03-13-2019, 03:51 PM)Mark Hygate Wrote: Is it not more - if not at least equally - likely that someone multiplies 60 x Centurions/Centuries by 100 to get 6,000.

Yes, I suppose so. Writers throughout Roman history seem to have assumed a general size for a legion, often six thousand, and could well have calculated it in just this way. My point was that the reference in question was to the legion of the principiate, not the later era.
Nathan Ross
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Since Rufinus lived in the 4th century, I was thinking of the Chronography of 354.

Maxentius ruled 6 years… They lynched the Romans of the soldiers of Moesia and 6,000 Roman men were killed by the soldiers.

http://www.tertullian.org/fathers/chrono...f_rome.htm
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