The Late Roman Army - 451

[Magister Militum Flavius Aetius]

i've always imagined that aetius was struggling to keep the empire from falling apart. i wouldn't know if there was any prosper at all...
i think that empire from the 4th was considerably stronger than mid-5th empire.

it was clearly stronger - it had 90k men instead of around 40-50k. comparably to stilicho and ricimer's empires the empire was great.

[Valentinian Victor]

The entire gallic field army was a total of 20000-30000 ment, and the spanish and italian field armies and Aetius had a sizeable force to engage attila. I'm representing the lack of armor in IBUr by making all units below comitatenses (and most comitatenses won't have it either) have no armor except a helmet on some troop types. And don't forget Ammianus and Vegetius were writing at a time where the Empire was unstable and in a crisis. In aetius time the empire was prospering. And i'd agree with you on that number considering the amount of troops that were paid. The others were fighting out of loyalty and/or for plunder and women. The Visigoths could field an army of 20000 max (I think Hydatius mentions it), and they probably had about 15-20000 men at chalons. With an equal number of other barbarians making up the center.

Theodoric II mentions in 453 that Aegidius alone had 12000 troops of excellent quality/standing in the north gallic field army.

Without appearing to be rude, I think you need to increase your reading around this time frame. The Empire from the Reign of Constantine I to Theodosius I was in a far better condition than that ever achieved during the time of Aetius. Look at how many provinces were lost after 400AD, by 440AD practically all of Africa, Spain and Gaul were out of Roman hands and in the hands of the Vandals, Alans, Britons, Burgundians, Visigoths and Franks. The Late Empire reached its optimum under Valentinian I, and the Roman army under the joint reigns of Valentinian I and Valens is reckoned by a number of historians to have reached it absolute maximum (unless of course you take the view that it was actually larger from the early 370's when Valens began hiring Gothic troops for his proposed invasion of Sasanid Persia).

The army raised for the abortive invasion of Africa in 468AD was considered a huge force by the ancient authors, and this force was reckoned at approximately 30,000 troops in total. That shows how pitiful the forces at the desposal of the Empire were by that date. Julian raised approximately 60+ thousand for his invasion of Sasanid Persia, Valen's may have achieved 90+ plus had not the events of 376-378AD not got in the way. And whilst both Julian and Valens forces did contain Gothic mercenary forces, they were in no way on the scale of the numbers of barbarians employed by the Romans from the reign of Thoeodosius I onwards.

[juvenus]

btw, the Roman army from 451 isn't just the western army...i wonder how many barbarians were employed in the eastern army of the period?

[Flavius Vegetius Renatus]

I second that VV. Theres no doubt empire was in far better shape durign reigns of Constantine and Theodosius and its a total absurd to draw parallel to time of Aetius. I will even add that whatever was left of the WRE during short reign of Majorian was much better off than that of Aetius' and if it wasnt for few setbacks incurred by that emperor (destruction of the fleet by vandals and betrayal of Ricimir) we would probably be speaking today of him as the last great Roman.

[SeniorBatavianHorse]

I may be wrong here - and I am quoting from memory - but doesn't Sidonius Apollinaris state that, having seen the army of Aetius, that he was shocked by how raw and how small it was - that the Roman troops had not even drawn their swords from their scabbards, meaning that they were untried recruits? If my memory is right, then no matter what we personally believe or want to believe, here is one man who saw the troops of Aetius marching to engage Attila comment on how small and poor it was. His word alone - rhetoric aside - negates any wishful thinking to the contrary.

And I completely agree about Majorianus! A very energetic Emperor in that last days of the western Empire!

edit: I have this list of references to Aetius in the writings of Sidonius but don't have access to the works at the moment:

Aëtius. VII. xii. 3. The famous general, who defeated Attila, and was murdered by Valentinian III. Also mentioned in Carm. v, vii, and ix.

Further Edit:

OK - found this as well:

Battle
Upon learning of the invasion, the "Magister militum" Flavius Aetius moved quickly from Italy into Gaul. According to Sidonius Apollinaris he was leading forth a force consisting of few and sparse auxiliaries without one regular soldier. [Sidonius Apollinaris, "Carmina" 7.329f.] He immediately attempted to convince Theodoric I to join him. The Visigothic king learned how few troops Aëtius had with him and decided it was wiser to wait to oppose the Huns in his own lands. Aetius turned then to the powerful local magnate Avitus for help, who was not only able to convince Theodoric to join with the Romans, but also a number of other wavering "barbarians" resident in Gaul [Sidonius Apollinaris, "Carmina" 7.332–356.] . The combined armies then marched for Aurelianum, reaching that city about June 14.

[juvenus]

According to Sidonius Apollinaris he was leading forth a force consisting of few and sparse auxiliaries without one regular soldier. [Sidonius Apollinaris, "Carmina" 7.329f.]

I would just warn other members about an interesting confusion on the part of Sidonius here.
He didn't consider troops under Aetius as the regular soldiers. Yet, he called them "auxiliaries". This is a complete nonsense. Auxiliaries were regular troops.
The link provided by SBH is of not much use, however, since the late auxilia were different than those from the Principate era. Late auxilia came into existence during the regency of Constantius (father of Constantine the Great) when he recruited Alammani on the Rhine-the very first auxilia unit ever was named "Regii". And they were all graded as palatina-the highest grade (source: prof. Michael Speidel: "Auxilia Palatina").
If Aetius led any such "auxiliaries" then they were totally regular soldiers. It is not known, however, when auxilia palatina disappeared from the Roman order of battle. By the time of Aetius those auxilia palatina might have been long gone as the individual regiments.

Perhaps Sidonius was using the term "auxiliaries" in a general meaning. For him, it might have meant foederates or numerii (considered to have been semi-regular) OR-he was talking about Aetius' private retinues/bodyguard?

[Valentinian Victor]

I would just warn other members about an interesting confusion on the part of Sidonius here.
He didn't consider troops under Aetius as the regular soldiers. Yet, he called them "auxiliaries". This is a complete nonsense. Auxiliaries were regular troops.
The link provided by SBH is of not much use, however, since the late auxilia were different than those from the Principate era. Late auxilia came into existence during the regency of Constantius (father of Constantine the Great) when he recruited Alammani on the Rhine-the very first auxilia unit ever was named "Regii". And they were all graded as palatina-the highest grade (source: prof. Michael Speidel: "Auxilia Palatina").
If Aetius led any such "auxiliaries" then they were totally regular soldiers. It is not known, however, when auxilia palatina disappeared from the Roman order of battle. By the time of Aetius those auxilia palatina might have been long gone as the individual regiments.

Perhaps Sidonius was using the term "auxiliaries" in a general meaning. For him, it might have meant foederates or numerii (considered to have been semi-regular) OR-he was talking about Aetius' private retinues/bodyguard?

Not all auxilia were 'regular' troops. Julian took 'skythian auxilliaries' with him on his Persian expedition, now believed to be Goth's hired for the purpose. There is a thought that when Goth's and other similar barbarians were recruited they initially fought in their native manner, but if they remained in Roman service beyond the terms of their employment they were then enrolled into 'regular' auxila units and received drill and training like the other regulars.

[juvenus]

There is a thought that when Goth's and other similar barbarians were recruited they initially fought in their native manner, but if they remained in Roman service beyond the terms of their employment they were then enrolled into 'regular' auxila units and received drill and training like the other regulars.

yep, i think so.

peter heather mentions it - lemme check i have his book.
hydatius chronicle 154

thanks for the info mate. does hydatius give any clue whether "that" Aetius was actually MMFA that we know? I doubt that name Aetius was very much common...

good pint pomps... i didn't thjink of that but it is likely that they were - also the average fort was maintained by about 200-500 soldiers (depending on the size etc.) so i made a reasonable guess based on that (about 6 fortresses, with his estates scattered throughout the empire)

it sounds as if Aetius had his own empire

[wulfgar610]

I would just warn other members about an interesting confusion on the part of Sidonius here.
He didn't consider troops under Aetius as the regular soldiers. Yet, he called them "auxiliaries". This is a complete nonsense. Auxiliaries were regular troops.

I don't think they were referring to "Auxuilliaries" in the form they existed during most of the Imperial period. From Augustus onwards "Auxiliaries" were regular troops. But by this period regular troops who retained "auxiliary" in their name were not auxiliaries in the classical meaning of the word. With the loss of the distinction of citizen and non citizen, the basis of distinction between regular troops was lost. In the 5th century AD, the term was referring to what it had originally, foreign barbarian troops.
There was still a Western Roman army, but mostly irregulars who were evolving into robber barons.

Regular troops are expensive an time consuming to create and maintain. The Western Empire simply couldn't pay them.

[juvenus]

I don't think they were referring to "Auxuilliaries" in the form they existed during most of the Imperial period. From Augustus onwards "Auxiliaries" were regular troops. But by this period regular troops who retained "auxiliary" in their name were not auxiliaries in the classical meaning of the word. With the loss of the distinction of citizen and non citizen, the basis of distinction between regular troops was lost. In the 5th century AD, the term was referring to what it had originally, foreign barbarian troops.
There was still a Western Roman army, but mostly irregulars who were evolving into robber barons.

Regular troops are expensive an time consuming to create and maintain. The Western Empire simply couldn't pay them.

yes it seems the term auxiliaries was used in a global meaning in the 5th and not to refer to auxilia palatine as I thought.

I don't have the full picture MMFA. It really came down to trade and especially sea trade and the comparison of the eastern and western ends of the Mediterranean. In the early classical era the Western End had blossomed due to Spanish Silver. It's estimated that 3/4's of the worlds silver was being mined there at the time. The currency debasement began in the 2nd century, so I suspect the silver mines output was beginning to decline then. Just as we have hit "peak oil" today, the Roman Empire hit "peak silver". After 200 AD sea trade seems to have declined.

The Eastern part which was still more profitable with cash crops, declined under the burden of taxation to support the West. The last time the West had money was with the treasury split in 395. Everything I come across supports the historical view of Western Bankruptcy in the 5th century. We hear constant moans form foederati about not receiving supplies or money. It was common that pay was highly irregular by this late era.

The promised pay for the basic regular foot trooper was 5 solidi gold, or equivalent in silver or copper. In fact most people only saw silvered bronze coins called follies. But that didn't include the cost of equipping, feeding and clothing them.

Even barbarians who where given a plot of land, still needed money to acquire cash crops, grain, olive oil.........and wine, to make life bearable.

Because the mobile army couldn't live on a plot of land, they would have cost more.

Estimates in the link conclude that a foot soldier cost an average of 30 solidi a year to keep, and you could almost double that for cavalry.

The revenue of the Eastern empire was about 7.5 million solidi at the time. Maintaining a 150k strong force would have take 5.5 million of that. I'd suspect the West may have only had half that revenue. Western finances were stretched way past breaking point.

It might be a difficult study, but understanding the economics is a serious issue for a historical war game.

Excellent post understanding of the late roman economy is one the underestimated issues. However, it would be very useful to know more about it. it would cast a different light on some things and make our understanding of the period a lot more deeper.
We would probably end up shocked by the knowledge of how pathetic WRE's finances were. No wonder the West fell under military pressure. On the other hand, ERE's finances were definitely the key reason why the East survived.
I think the eastern court supported the west for as long as they could. unfortunately, when their situation became precarious too - alas, the west was no more.

[wulfgar610]

yes it seems the term auxiliaries was used in a global meaning in the 5th and not to refer to auxilia palatine as I thought.



Excellent post understanding of the late roman economy is one the underestimated issues. However, it would be very useful to know more about it. it would cast a different light on some things and make our understanding of the period a lot more deeper.
We would probably end up shocked by the knowledge of how pathetic WRE's finances were. No wonder the West fell under military pressure. On the other hand, ERE's finances were definitely the key reason why the East survived.
I think the eastern court supported the west for as long as they could. unfortunately, when their situation became precarious too - alas, the west was no more.

I'm left wondering about the use of the distinction for legionnaire units and units which still had auxiliary as part of their nomenclature. Was there any real difference between these bodies of line troops by the 5th century?

Thanks for the complement. Our modern western machine age lifestyle is so rich in material terms. For the average person of the classical times a loaf of bread was a substantial part of their daily earnings. If the RE had a population of 100 million at it's height, probably half of these were living below the what we could conceive of as subsistence.
Today you can buy a full Roman solders kit for a few thousand dollars online. Back then it was worth a few years of common labor. The minimum wage in the USA may be about $15,000 annually today, so in today's terms that basic infantry kit was worth perhaps about $75,000.
In the early RE the kit was supplied as a loan which was subtracted from pay over years of service. The "State" repurchased the kit at the end of service. The late RE seems to have supplied and retained kit as state property.
Towards the end the money economy broke down due to the relative scarcity of gold and silver. The silver bronze currency was only good for the local economy and distant traders wouldn't take them. Only gold and silver were efficient for long distance trade.
The monetary policies of the RE aided its own destruction.

The Eastern part of the Empire was brought down supporting the West. After the final split the Eastern economy began to recover.

[SeniorBatavianHorse]

Ignore the hyperlink - that came with the article I found on the net. Sidonius is merely using an archaic term here - I was posting hurriedly and didn't pause to check the online link. I apologise for that!

I'd like to quote a pm PM sent me a while back regarding Jordanes when I was doing some research on Chalons for an online tournament (shudders with the memory!) - I hope he won't mind:

Thanks for the quick reply. Aetius was quoting your post on Aetius and his Romans in the thread here -

http://twcenter.net/forums/showpost....47&postcount=2

My only source which mentions actual troops from a personal perspective - Sidonius Apollinarus in his poem Carmina - I can't find in translation but another writer says that Sidonius mentions troops who had not yet even drawn their swords. Of course, it could be rhetoric!

Our problem is that no military specialist wrote down the story. Even the chronicles of the unknown are terrible.

One of our main sources which tells us a little bit more about parts of his (Aetius) troops is Jordanes (Iordanes Get 191.)
Hi enim adfuerunt auxiliares: Franci, Sarmatae, Armoriciani, Liticani, Burgundiones, Saxones, Ripari, Olibriones, quondam milites Romani, tunc vero iam in numero auxiliarium exquisiti, aliaeque nonnulli Celtcae vel Germanie (!) nationes.

It is no problem for us to identify most of this troops. Most of them are Foederatii (Frances or Burgundiones) and troops from the coast (Saxones). Also the Armoriciani were Foederatii.
Next to this we find the genuin word (the authentic word) "roman troops".
But this so called roman troops are also sometimes called "gentiles". Even today it is still a spanish word "gentes". And that means "people".

In this case the romans saied gentiles romani to the Sarmatae as well as to the Laeti. Laeti can be a local troops, but sometimes in combination with "Latin"-troops.

I think that only the real core of Aetius troops were "real"roman troops. Perhaps 2000-4000 elite-men. That would explain the nice word "exquisiti" in combination of the roman "auxiliarii".
Carefully choosen. The best of the best! (Auxilia Palatinae??? - I think so)
Then we don't find any words about the roman exercitus - the legiones.
So, nobody can tell you which Legion was part of the battle. And nobody knows if there were Legions. But it is very possible because we hear in other sources that Aetius always marched with his exercitus.
The rest of the "semi-romans" was deployed by mounted Sarmatians and local Milites. That's for sure.
And that's all!

Unknown is the identification of the Ripari and Olibriones.

Missing in this list (and I wrote that in my late antique guide) are the Alani and the goths. So even this list is not complete.

How do we square this with Sidonius and his shocked rhetoric? We must remember that Jordanes is writing after Cassiodorus and by memory AND praising Gothic history and its arms in battle. His representation of the battle is neither accurate nor timely. Therefore his list above is a tentative one at best - it should not be taken as a factual list. At best, it is a remembered order of battle and quite likely an inaccurate one at that. At worst, it is just colorful language and rhetoric.

Sidonius equally is a prejudiced writer but I don't have a translation of the poem in question and so cannot verify the idea that a] Aetius troops were few (the Romans ones that is) and that b] Sidonius was so shocked at their greenness that he referred to them as not even yet having drawn their swords! Any help here would be appreciated.

I value Sidonius as he was writing on the ground over Jordanes who wrote much later copying another book to his own agenda - but having said that (and to throw a spanner in my own works here) I have always thought the speech given by Attila (in which he pours scorn on the Roman troops on the field of battle) as being an example of classic belittling - if you read what Attila is actually saying outwith his scorn, he is indirectly praising the Roman auxilia palatinae and the accompanying milites: afterall, they successfully occupied a tactical position ahead of the enemy and secured it behind a well-ordered fulcum! Surely a sign of disciplined and well-motivated troops.

I posted over in RAT re this a couple of years ago - here - but alas the debate petered out.

[Magister Militum Flavius Aetius]

thanks for your input - but i don't see how his troops were few whan in both the chronicle of marcellinus and a report by theodoric II state that aegidius had 12000 field troops under his command in 452/3 and marcellinus in his chronicle reports that he had just as many, maybe more. That would have left majoran and ricimer a very depleted army. Also Hydatius reports that in 446 Vitus had a "considerable body of troops". Also not all of spain was lost as both catagenesis and tarraconesis were still roman, you had most of narbonesis I and II (narbona and massilia and arles) middle gaul and most of northern gaul (lugdenisis and belgica) under roman control. in the east only pannonia was lost and in the south tripolitania and all 3 mauretanias were still roman, and so were the mediterranean islands. Aetius clearly had a large body of troops. Marcellinus also reports that his troops were of better quality than the italian field army, which was mostly foederati under ricimer.

I might also state that auxilaries were essentially aetius' huns - they served him under pay and roman command and were not foederati but were not roman regulars either - they were a mishmash.

also missing in that list are librones - mercenaries that were formerly field troops but now served as soldiers for hire - some of them fought out of loyalty because of their experiences with aetius

[Magister Militum Flavius Aetius]

Based on many sources - including modern ones - peter heather states that by 445:

"...must have implied a decline in miltary numbers of getting on for 40000 infantry, or in excess of 20000 cavalry."

Taking this into account aetius could have fielded an army of 50000-70000 men. Probably taking a combnation of the two it would bring him down to about 50000 max.
these would have been of verying quality - IMHO about 10000 limitanei 30000 field 10000 cavalry - this is all based on the pay of 6 solidi infantry 10.5 cavalry

[Valentinian Victor]

Based on many sources - including modern ones - peter heather states that by 445:

Taking this into account aetius could have fielded an army of 50000-70000 men. Probably taking a combnation of the two it would bring him down to about 50000 max.

But, that figure of 50000 is probably the TOTAL Western military strength, the absolute maximum number of field army troops that could, just could, be put together to form an army. This would have meant stripping the defenses of the Western Empire of forces that were barely able to contain the barbarian incursions, and I canot see anyone with the calibre of Aetius doing that. No, he probably drew together a Roman force much smaller than that number and bolstered it with barbarian mercenaries/feoderatii.

[Magister Militum Flavius Aetius]

i just said that - read the edit
and those troops would have been variously dispersed - the majority in gaul

[Pompeius Magnus]

As I tried to explain that before (btw: with primary source-texts): the huns of Aetius can be described as mercenaries. They were paid foreign warriors.
But we can give some examples (even names) of soldiers who get access to the private corps of Aetius' Bucellarii. So, obviously some (few) of them served in semi-regular units.
And Heather is talking a lot in his book. There are some debatable statements which are not backed up by primary sources. The last real academic elaboration of Aetius, his early life and all known sources can be found in Timo Sticklers book.

Another thing which is many times misinterpreted, overrated or misunderstood is the importance of the west roman army at all in 440 to 450.
The west roman empire was - independently if there were some elite units left (this was for sure the case) - at this time (+/-440AD) dependent on the east roman empire regarding the discreption and support of naval fleets AND the protection of Dalmatia and the western danube area.
That explains the dynamic number of available troops within 2 dates - available for west roman commanders.
Sometimes the number of the field army was higher, 5 years later the number was lower, and another 5 years later the number was increasing again.However, all this doesn't say anything about the real strength of the western army. The dynamic of that time was increadible high in the west. Many influences were responsible for that. The eastern empire in general and its support, the own allies, foederatii, new barbarian invasions etc. Whenever the east was able to help the west - then the west was able to remove troops from one province and move them to another to support other field armies. In this case it was of course possible to deploy 25.000 men - temporarily.

Another interesting example is when Attila planned and performed his 2nd expedition to Italy in 452. He destroyed the complete north of Italy and was finally stopped by a plague or an epidemic within his own army. There was no Roman army capable to stop the huns.
However, recently we have a description of a west-roman man called Aetius who came with an east-roman army from the east with the intention to attack the huns.
If this man is our famous Aetius, or another officer called Aetius is still not evidenced - but this example shows that the west had obviously problems to stop the 2nd invasion of the huns in Italy by own ressources.
Another story about an eastern army which marched deep into hunnic core land to disburden the west can be found here: Hydat. Chr. ann. 452

...
The description of Iordanes is probably - but this is just my own opinion - the most accurate we can find - even if he had just 3 days time to read the script of Cassiodorus.

auxiliarium exquisiti - is debatable, probably Auxilia Palatinae or well equipped Auxilares in general.
It is also important to mention that the classification between Palatinae, Auxiliae and regular Comitatenses was still valid during the reign of Justinian. I say that because Iordanes wrote his book in the 530s.
But since the mid 6th century the original designation of those Palatinae units was nearly completely gone. Also due to the fact that all units were classified as Numeri or Arithmoi. However, we can suggest that Iordanes had still a very good idea about the different troop-types of the mid/late 5th century.
milites Romani - The western Milites of the mid 5th century were not really the same as the Milites of the East in the mid 6th century. But if they were Legions or New-Legions then he would use the word Numerus. This is not the case, so the Milites were probably just Milites.

Furthermore we know that Aetius had private retainers. Obviously they were strongly roman organized, otherwise I can't explain why they were still serving under Valentinian III after the death of Aetius.
Finally, and more important are the rare infos about his exercitus as mentioned above. And here we will find - and I have no doubt about it - also the old Legions. Exercitus doesn't necessarily mean that we are speaking about Legions only, also other troop-types can be found here. It means everything and nothing. Anyway.
If this Exercitus marched to the Catalaunian plains is according my knowledge unknown. But I personally think so.
And yes, a transitional number of 15.000 to 25.000 roman soldiers - or soldiers under roman standards - is possible. And togehter with the Alani - a group wich was settled by Aetius some years before in gaul - and the Sarmatae (semi-roman troops) Aetius was probably able to deploy more than 25.000. But then the maximum of available troops is reached.

And this explains also the total number of 35.000 up to 55.000 men (including allies and foederati) - a number which is given and suggested by all staid modern historians.

[juvenus]

However, recently we have a description of a west-roman man called Aetius who came with an east-roman army from the east with the intention to attack the huns.
If this man is our famous Aetius, or another officer called Aetius is still not evidenced

Where'd you learn of this?

[Valentinian Victor]

As I tried to explain that before (btw: with primary source-texts): the huns of Aetius can be described as mercenaries. They were paid foreign warriors.
But we can give some examples (even names) of soldiers who get access to the private corps of Aetius' Bucellarii. So, obviously some (few) of them served in semi-regular units.
And Heather is talking a lot in his book. There are some debatable statements which are not backed up by primary sources. The last real academic elaboration of Aetius, his early life and all known sources can be found in Timo Sticklers book.

Another thing which is many times misinterpreted, overrated or misunderstood is the importance of the west roman army at all in 440 to 450.
The west roman empire was - independently if there were some elite units left (this was for sure the case) - at this time (+/-440AD) dependent on the east roman empire regarding the discreption and support of naval fleets AND the protection of Dalmatia and the western danube area.
That explains the dynamic number of available troops within 2 dates - available for west roman commanders.
Sometimes the number of the field army was higher, 5 years later the number was lower, and another 5 years later the number was increasing again.However, all this doesn't say anything about the real strength of the western army. The dynamic of that time was increadible high in the west. Many influences were responsible for that. The eastern empire in general and its support, the own allies, foederatii, new barbarian invasions etc. Whenever the east was able to help the west - then the west was able to remove troops from one province and move them to another to support other field armies. In this case it was of course possible to deploy 25.000 men - temporarily.

Another interesting example is when Attila planned and performed his 2nd expedition to Italy in 452. He destroyed the complete north of Italy and was finally stopped by a plague or an epidemic within his own army. There was no Roman army capable to stop the huns.
However, recently we have a description of a west-roman man called Aetius who came with an east-roman army from the east with the intention to attack the huns.
If this man is our famous Aetius, or another officer called Aetius is still not evidenced - but this example shows that the west had obviously problems to stop the 2nd invasion of the huns in Italy by own ressources.
Another story about an eastern army which marched deep into hunnic core land to disburden the west can be found here: Hydat. Chr. ann. 452

...
The description of Iordanes is probably - but this is just my own opinion - the most accurate we can find - even if he had just 3 days time to read the script of Cassiodorus.

auxiliarium exquisiti - is debatable, probably Auxilia Palatinae or well equipped Auxilares in general.
It is also important to mention that the classification between Palatinae, Auxiliae and regular Comitatenses was still valid during the reign of Justinian. I say that because Iordanes wrote his book in the 530s.
But since the mid 6th century the original designation of those Palatinae units was nearly completely gone. Also due to the fact that all units were classified as Numeri or Arithmoi. However, we can suggest that Iordanes had still a very good idea about the different troop-types of the mid/late 5th century.
milites Romani - The western Milites of the mid 5th century were not really the same as the Milites of the East in the mid 6th century. But if they were Legions or New-Legions then he would use the word Numerus. This is not the case, so the Milites were probably just Milites.

Furthermore we know that Aetius had private retainers. Obviously they were strongly roman organized, otherwise I can't explain why they were still serving under Valentinian III after the death of Aetius.
Finally, and more important are the rare infos about his exercitus as mentioned above. And here we will find - and I have no doubt about it - also the old Legions. Exercitus doesn't necessarily mean that we are speaking about Legions only, also other troop-types can be found here. It means everything and nothing. Anyway.
If this Exercitus marched to the Catalaunian plains is according my knowledge unknown. But I personally think so.
And yes, a transitional number of 15.000 to 25.000 roman soldiers - or soldiers under roman standards - is possible. And togehter with the Alani - a group wich was settled by Aetius some years before in gaul - and the Sarmatae (semi-roman troops) Aetius was probably able to deploy more than 25.000. But then the maximum of available troops is reached.

And this explains also the total number of 35.000 up to 55.000 men (including allies and foederati) - a number which is given and suggested by all staid modern historians.

That term 'auxiliarium exquisiti', I wonder if that is a corruption of 'auxiliarium expediti' (light armed auxilliaries)?. Milites is just a general term for infantry, it could be palatine legiones or limitanae

[Pompeius Magnus]

That term 'auxiliarium exquisiti', I wonder if that is a corruption of 'auxiliarium expediti' (light armed auxilliaries)

indeed an interesting point and of course possible ...even if it's speculative