The Size of the Roman Army at Mons Graupius 83 AD

[Monad]

https://www.academia.edu/166041503/The_Size_of_the_Roman_Army_at_Mons_Graupius_83_AD

[stevenneate]

Nice work. One minor correction - on page 1 the legion present was the XXth Valeria Victrix, not the XIIth.

Otherwise, the paper strengths of Agricola's forces are all we have to go on, and ancient historians would have gone on these as well. Daily reports from the front would not have been part of their narrative! Given the usual numbers unfit for duty, camp garrison and general laggards, I don't believe these numbers would have been drastically reduced. Agricola was well supplied with a base at Monifieth at the mouth of the River Tay. Whilst he fought his way through Maetae territory, it was relatively trouble free from there in comparison. The Caledonians had gathered for a fight, rather than their usual hit and run, so the position they chose must have seemed like the strongest army-sized defensive position or Agricola was close to hitting something important to the prestige of Calgacus that had to be defended.

Inchtuthil, as a "legionary" fortress, was 53 acres in size and if the camp at Logie Durno is indeed Agricola's camp, it is 3 times the size of this at 145 acres. This is enough space to accommodate Agricola's force. A very worthwhile study is Dr Rebecca H. Jones's "Roman Camps in Scotland" (Society of Antiquaries of Scotland, ISBN: 978-0-903903-50-9, 2011).

My pipe dream would be that someone, one day, discovers the battlefield and it might fill in some gaps in our knowledge. This may give us a better guide to the potential size of the Caledonian force but until then, anything from 10,000 to 30,000 is feasible if the tribes were gathered to make a stand under an influential leader.

There is also a paper on the derivation of the name Calgacus by Adrian Grant at: https://independent.academia.edu/s/4b4fa366c8.

[Monad]

One minor correction - on page 1 the legion present was the XXth Valeria Victrix, not the XIIth

Yes, that was pointed out to me in the discussion group. Next, after Mons Graupius in my research was Arrian's Expedition, which involves the 12th legion. I did a cut and paste of the legion numbers from Arrian because I had already upper superscripted the legion numbers and after pasting forgot to change the 12th legion to the 20th legion. Also spelt Calgacus with a G instead of a C.

Otherwise, the paper strengths of Agricola's forces are all we have to go on, and ancient historians would have gone on these as well.

Exactly, and I cannot see why others on the discussion cannot realise that. Tacitus' numbers are rounded as are most numbers in the primary sources. I believe they do historically represent Agricola's force, so Tacitus had a good source, as did Plutarch's 88,000 Romans and allies at Cannae, which includes officers and supernumeraries, and are rare. Tacitus' numbers when unrounded, align with the rest of the unit and army numbers for the principate. Arrian's expedition is interesting as he has left all those troops with the minimum campaigns behind to protect the camp before setting out to engage the Alani, so from my research, this means the numerus organisation comes into play. Many believe the numerus represents any number of troops, but I disagree.

This may give us a better guide to the potential size of the Caledonian force but until then, anything from 10,000 to 30,000 is feasible if the tribes were gathered to make a stand under an influential leader.

Unfortunately, I have found, which is backed with four volumes of evidence, is enemy numbers have been concocted from the Roman army or fleet that faced them. Mons Graupius is no different. The red flag for me with Mons Graupius is when Tacitus provides the numbers for the auxiliary and cavalry, and yet omits the number of legionaries. The reason behind this is to cover up how the size of the Caledonian army was constructed. For example, during the First Punic War, a consular fleet would leave Italy and arrive at Messena and leave 32 ships as its revictual fleet. The consular fleet would then sail on to wherever it was going with the rest of the fleet. So, two consular fleets would leave 64 ships at Messena. Now look at the Carthaginian ships captured at Ecnomus in 256 BC:

Polybius 64 ships
Eutropius 64 ships
Orosius 64 ships
AVI 63 ships

As the Carthaginian commander is reported to have escaped, the author of the AVI has deducted this from the 64 Carthaginian ships captured. However, if no one knew that the Romans left a revictual fleet somewhere, those 64 captured Carthaginian ships would have no relevance. Oh, nearly forgot, for 251 BC, Polybius (1 39 9) reports that consuls Lucius Caecilius Metellus and Gaius Furius Pacilus were despatched to Sicily with "some legions" and 60 ships to revictual the legions, which has been rounded from 64 ships.

There is also a paper on the derivation of the name Calgacus by Adrian Grant

Grant is also part of the discussion and I have his paper. It is quite interesting.

[Ian61]

I can't access the pdf I just get 'something went wrong' but this is one of those battles that 'might have been' whilst Agricola probably had a fight up there it may well have been bigged-up by Tacitus. (I am a huge fan of the Agricola as a brilliant and we'll crafted narrative but this doesn't mean I believe it.)

[Imperial Dave]

The Calgacus discussion is a nice side note btw.

[Monad]

Grant has a paper and discussion underway on his position of the location of the battlefield of Mons Graupius:

https://independent.academia.edu/s/249535ad87?source=link

[Imperial Dave]

Thanks. Grant is quite prodigious in terms of writing stuff

[michaellaneuk]

I have read the article and do think some of the assumptions made by the author are a little difficult to accept.

First he appears to have no knowledge at all of the composition of the then garrison of Roman Britain.  He assumes that all the auxiliary infantry are from Cohortes Equitatae each with a full strength of 480 infantry and 120 Cavalry.  This ignores the fact that there are also numerous Cohortes Peditatae in the Garrison of Britain,which, if quingenaria units, were each at full strength 480 strong (but with no cavalry contingent) but he ignores the likelihood that any of the Cohortes, both equitata and peditata, might have been milliara units, ie approximately double strength which again at full strength might be 800 infantry (10 centuries) for both types of auxiliary but adding 240 cavalry to the Cohors Equitata. 

 My suspicion is that the Romans regarded Cohortes Equitatae as having more of a garrison role, their mounted contingent being useful for scouting duties from an isolated fort (or indeed forts).  I do not think therefore that all the Auxiliary infantry would have been from Cohortes Equitatae.  The Cohortes Peditatae resemble the legionary cohort in organisation so might be more suited for a stand up battle. 

Though Josephus mentions Vespasian taking Milliaria units with him into Galilee at the start of his campaign during the Jewish War, archaeological evidence suggests that the Milliaria Cohortes and Alae were introduced under the Flavian dynasty of which, of course, Domitian was the last and the Emperor under whom Agricola was governing Britain.

Next the cavalry which the author assumes was made up of the four 120 strong mounted contingents of all the Legiones then in Britain (which he oddly calls Equites Singulares) plus the mounted contingents of the Cohortes Equitatae which he assumes supply all the Auxiliary infantry.  Here he entirely ignores the existence in Britain of a number of Auxiliary Alae either quingenaria units of 480 horsemen or, if milliaria, 720 cavalry, again all if at full strength.  These units were undoubtedly the best cavalry in the province and would without any doubt have formed the core, if not all, the cavalry that Agricola took to Mons Graupius. 

 I am not convinced by the suggestion that all the legionary cavalry in the province were formed into an ad hoc unit when fully trained and full strength auxiliary Alae were available, some of which were very high quality indeed. 

I do not believe that such legionary cavalry would have been called "Equites Singulares".  Such a unit is mentioned as part of the Emperor's Guard in Rome while Tacitus does mention another such unit on the upper Danube, in either Raetia or Noricum in AD 69.  I think this was a Governor's bodyguard unit and, given its location, I think it was unlikely to be as strong as an Auxiliary Ala.  Other such units of varying strength probably existed and indeed quite likely one might have been with Agricola himself in Britain.  However who is to say?  We can but guess.

Finally the author assumes each Legion supplied a Vexillation of two Cohortes giving a strength of only eight Cohortes altogether - less than a quarter of the then Legionary strength in Britain.  Given this was a major campaign, I would be surprised if Agricola did not take a rather larger force of legionaries with him into Caledonia.

[Monad]

First he appears to have no knowledge at all of the composition of the then garrison of Roman Britain.  He assumes that all the auxiliary infantry are from Cohortes Equitatae each with a full strength of 480 infantry and 120 Cavalry. 

I did provide my reasoning for using the Cohortes Equitatae: "As Tacitus gives the name of a praefectus cohortis being killed, which is associated with a part-mounted quingenary cohort, Tacitus' figure of 8,000 auxiliary infantry has been interpreted to be organised into 16 part mounted auxiliary quingenary cohort (480 auxiliary infantry and 120 auxiliary cavalry."

This ignores the fact that there are also numerous Cohortes Peditatae in the Garrison of Britain

Well, as the cavalry numbers matched the infantry, I went with Cohortes Equitatae and because of the other reason given above. I have also ignored how many slaves owned by the Roman military, doctors, transports personal, carpenters and blacksmiths. This is because Tacitus did not provide numbers for them at Mons Graupius. Had he done so, I would have included them.

he ignores the likelihood that any of the Cohortes, both equitata and peditata, might have been milliara units, ie approximately double strength which again at full strength might be 800 infantry (10 centuries) for both types of auxiliary but adding 240 cavalry to the Cohors Equitata.

Can you prove a milliaria has 10 centuries?

My suspicion is that the Romans regarded Cohortes Equitatae as having more of a garrison role, their mounted contingent being useful for scouting duties from an isolated fort (or indeed forts).  I do not think therefore that all the Auxiliary infantry would have been from Cohortes Equitatae.

Suspicion is not evidence.

archaeological evidence suggests that the Milliaria Cohortes and Alae were introduced under the Flavian dynasty of which, of course, Domitian was the last and the Emperor under whom Agricola was governing Britain.

What archaeologist suggests is not evidence.

Next the cavalry which the author assumes was made up of the four 120 strong mounted contingents of all the Legiones then in Britain (which he oddly calls Equites Singulares) plus the mounted contingents of the Cohortes Equitatae which he assumes supply all the Auxiliary infantry.  Here he entirely ignores the existence in Britain of a number of Auxiliary Alae either quingenaria units of 480 horsemen or, if milliaria, 720 cavalry, again all if at full strength. 

Can you provide proof of milliaria of 720 cavalry? Second, on the Equites Singulares, please read my paper

https://www.academia.edu/124269078/The_Size_and_Organisation_of_the_Equites_Legionis_and_the_Equites_Singulares

and also this paper:

https://www.academia.edu/124417625/An_Examination_of_the_Roman_Cavalry_according_to_Hyginus

These units were undoubtedly the best cavalry in the province and would without any doubt have formed the core, if not all, the cavalry that Agricola took to Mons Graupius.

Opinion is not evidence.

I am not convinced by the suggestion that all the legionary cavalry in the province were formed into an ad hoc unit when fully trained and full strength auxiliary Alae were available, some of which were very high quality indeed.

Again opinion.

do not believe that such legionary cavalry would have been called "Equites Singulares".  Such a unit is mentioned as part of the Emperor's Guard in Rome while Tacitus does mention another such unit on the upper Danube, in either Raetia or Noricum in AD 69.

https://www.academia.edu/124269078/The_Size_and_Organisation_of_the_Equites_Legionis_and_the_Equites_Singulares

Other such units of varying strength probably existed and indeed quite likely one might have been with Agricola himself in Britain.  However who is to say?  We can but guess.

When you say "We can but guess," well that defeats your former criticism.

https://www.academia.edu/124269078/The_Size_and_Organisation_of_the_Equites_Legionis_and_the_Equites_Singulares

Finally the author assumes each Legion supplied a Vexillation of two Cohortes giving a strength of only eight Cohortes altogether - less than a quarter of the then Legionary strength in Britain.  Given this was a major campaign, I would be surprised if Agricola did not take a rather larger force of legionaries with him into Caledonia.

Again, your opinion does not make me wrong. I can tell from you reply that you have not studied all the data in the ancient sources for the principate relating to the vexillation. If you did undertake such a study, you will be better informed.

From numbers of infantry and cavalry provided by Tacitus, of which I have only worked with, and my numbers for vexillations and the cavalry adhere to the Roman military organisation of the whole period of the principate. I don't take data out of content and make it fit some preconceived theory. All the data in the ancient sources are consistent for the principate. It is one of the easiest period to understand.

You Michael, like so many other on this forum, do not address the question as to why does my data conform to Tacitus. The pattern on this forum has been to ignore them completely and try and find other superficial ways to prove I am wrong. I do understand that many do not like their preconceived reality to be challenged. Here is a question to the forum, which still has not been answered, but I will ask again. Please direct me to a study from academia that has completely examined all the data in the primary sources. My answer is there is none, and all academics writing on the Roman army have done nothing more than cherry pick the information they want that adhere to their theory. Because of this mass failing, academics have built a picture of the Roman army based on mathematical mistakes made by the ancient historians. You have built your foundations on sand.

"In 198 BC, Sextus Aelius Paetus Catus and Titus Quinctius Flaminius were elected consuls. Sextus Aelius Paetus Catus was allocated the province of Italy. Titus Quinctius Flaminius was assigned Macedonia, with 3,000 Roman infantry, 300 Roman cavalry, 5,000 allied infantry and 500 allied cavalry so as to bring the legions up to their proper strength. (Livy (32 Livy writes that the consul Sextus Aelius Paetus Catus was to be provided with a completely new consular army. Livy states the praetors on reaching their provinces were to disband the old infantry and cavalry, which means those infantry that had completed their 5th campaign and those cavalry that have completed their 6th campaign are to be discharged and sent back to Italy. The praetor Marcellus Claudius (Sicily), was to enrol 4,000 allied infantry and 300 allied cavalry. The praetor Marcus Porcius Cato (Sardinia) was to enrol 2,000 infantry and 200 cavalry of the same class (allied infantry and cavalry). Livy's figures amount to 15,300 men, consisting of 14,000 infantry (3,000 Roman and 11,000 allied infantry) and 1,300 cavalry (300 Roman and 1,000 allied cavalry):

Consul Flaminius, 3000 Roman infantry, 300 Roman cavalry, 5000 allied infantry,   500 allied cavalry
Praetor Cato   2000 allied infantry   200 allied cavalry
Praetor Claudius   4000 allied infantry   300 allied cavalry

With the removal of the rounding, you get what? Anyone up to it? Also, besides the numbers, can anyone identify how many hastati, princeps, triarii and velites are included with each number? Or is it just one troop type? Why hasn't any academic studied these numbers?

[dwkay57]

I've just finished re-reading Alistair Moffat's "The Wall" in which he writes that the Ala Petriana which was stationed at Stanwix was the only known milliaria cavalry ala stationed in Britain.

In the late 1980's, I picked up a sheet from one of the museums along Hadrian's Wall that gave a breakdown for the Roman  Army, by province by unit type, as in AD150. The only reference is that the information was prepared by Dr Paul Holder. But for what it is worth it lists for Britannia: 1 Ala Milliaria; 11 Ala Qunigenaria; 5 Cohors milliaria equitata; 2 Cohors milliaria peditata; 20 Cohors quingenaria equitata; and 21 cohors quinqgenaria peditata. How relevant, concurrent, accurate this is I don't know, but might be interesting or otherwise.

When I last visited Housesteads on Hadrian's Wall, one of the information boards indicated that a milliaria cohort had 10 centuries. This seemed to contradict what I knew about the first cohort of a legion being 5 double centuries. I did query this with English Heritage and their response indicated that the 10 single centuries for an auxiliary milliaria cohort was based on the structure of remains of barrack blocks in the forts. Interpretation of stones in the ground and bumps in the grass is beyond me, but seems reasonable.

[michaellaneuk]

Good point by dwkay57.

Paul Holder is an excellent source on the Auxilia.  If any one is interested, his books on the Roman Auxilia include:

Paul A Holder 'The Auxilia from Augustus to Hadrian' in the B.A.R. International Series published in 1980. 

Paul A Holder 'The Roman Army in Britain' Batsford, 1982.

I made great use of both books, but especially the first, when I was writing my Roman Empire Order of Battle for the Civil War 69-70 AD published by our very own Society (still available to download for free from the Society's website).😇

I recently acquired a copy of "Roman Military Diplomas IV" co written by Margaret Roxan and Paul Holder and published by the Institute of Classical Studies, School of Advanced Study at the University of London in 2003.  I bought it (it's rather expensive but ...) as I wanted to see if there were any more recently discovered Diplomas to give more details of the Roman Auxilia - not that I plan an update to my book.😊

Margaret Roxan had written the previous three volumes but fell ill before this volume was completed and indeed died in 2003.

[michaellaneuk]

Just learnt that Paul Holder has added a fifth volume to the series on Roman Diploma.  Now I have to decide whether to buy one.

I did find some good one's in Volume IV.  Galba issued a Diploma of citizenship to a soldier in Legio I Adiutrix. As the Legion was recruited from the Fleet (who were non citizens) that confirms (or at least is a strong suggestion) that the men of the fleet were given citizenship at the start of their service rather than when they completed their years of service.  Fascinating.

One other snippet, a Diploma of Citizenship were issued under Severus Alexander to members of the Cohortes of the Praetorian Guard. That is rather odd given that the Guard was usually recruited in Italy itself (though perhaps less so at the start of the Third Century) and despite Caracalla (who is dubiously claimed as his father in Severus Alexander's titles on the Diploma) having made all free men in the Empire Roman Citizens (allegedly for tax reasons of course - plus ca change, plus c'est la meme chose!)