The two armies in the Imperial Presence late 4th C

[Colonel Chabert]

Hello all,

This is my first post on this excellent and informative forum.

I'm a collector of miniatures (little men), occasional wargamer and history enthusiast (especially military history).

I've been spending a lot of time recently on that part of Luke Ueda-Sarson's website dedicated to the Notitia Dignitatum and in particular to the Eastern army, some units of which I'm hoping to recreate on the tabletop. Mr U-S's musings on the origins of different units and their relationships are fascinating and, at least to my eyes, well argued. They raise questions which I know won't have any definitive answer but which I think might be interesting to discuss. At any rate I would be interested to read your views on them.

Firstly, when would the Praesental army have been split in two and why? Could it have been during the reorganization in 363/4 after the death of Julian or in 377/8 when Valens was preparing to "deal with" the Goths? Or later when Theodosius went west to fight the usurper Eugenius? Or even I suppose during earlier civil wars such as in 351? And why the split anyway? Theodosius effectively reigned alone in the east, his son Arcadius being only six years old when elevated to the purple and so hardly likely to be leading an army on campaign. Splitting the army meant that someone else, a potential rival, was left in command of a sizeable force which, given the paranoia of emperors of the time, seems surprising. If it was Valens who split the army, why did he not take his whole available force to combat the Goths? Even if the Romans underestimated the number of men the Goths could put in the field they still represented an immediate threat and success against them was by no means guaranteed so why not take every available man?

Secondly, and more specifically, Mr U-S argues convincingly that the two armies were split into near identical halves in such a way that in many instances matched pairs of units were broken up. It seems to be generally accepted that Late Roman infantry units usually acted in pairs, or brigades of two, and that these pairings were more or less permanent. Amongst the Auxilia Palatina of the two praesental armies however we often find one half of an apparent pair in one army and the other half in the other. For example in 9th place in the lists of Auxilia Palatina we find respectively the Defensores and the Vindices. These have similar names and similar shield patterns. Same in 10th place with the Raetobari and the Bucinobantes, in 11th place with the Anglevari and Falchovari and in 12th place with the Hiberi and Thraces. Why do this? There seems to be every advantage, tactically and psychologically, in keeping units together permanently so why split them up?

Your thoughts on these matters would be much appreciated.

Cordialement,

Colonel Chabert

[Robert Vermaat]

This is my first post on this excellent and informative forum.

Thank you very much. I Welcome and I hope many may follow.

Firstly, when would the Praesental army have been split in two and why? Could it have been during the reorganization in 363/4 after the death of Julian or in 377/8 when Valens was preparing to "deal with"the Goths? Or later when Theodosius went west to fight the usurper Eugenius? Or even I suppose during earlier civil wars such as in 351? 

When - nobody know for sure, but the first one (Valens and Valentinian take the throne after the death of Jovinus) is generally seen as 'the' moment. That does not mean though that this a totally new event, we know that sometimes units were split up in two (seniores and iuniores) on earlier occasions. No doubt it happenend afterwards as well. 
 

And why the split anyway? Theodosius effectively reigned alone in the east, his son Arcadius being only six years old when elevated to the purple and so hardly likely to be leading an army on campaign. Splitting the army meant that someone else, a potential rival, was left in command of a sizeable force which, given the paranoia of emperors of the time, seems surprising. If it was Valens who split the army, why did he not take his whole available force to combat the Goths? Even if the Romans underestimated the number of men the Goths could put in the field they still represented an immediate threat and success against them was by no means guaranteed so why not take every available man?

Why - volumes have been written about it. Why would Valens not take all? Because he was not sole emperor. Valentinian had of course died before Valens fought at Adrianople, but Gratian had succeeded him and would not have been eager to send all his troops to colleague in the East. He did go to Valens with reinforcements though, but Valens was unwilling to share the glory and did not wait. 

There seems to be every advantage, tactically and psychologically, in keeping units together permanently so why split them up?

I am not sure what your question is about, breaking up the pair or slipping the units in two? I will answer that second one. Current opinion is (but a hypothesis) that the units were split in two to add new recruits to them, until they were at full strength. Maybe splitting most units would forego any discussion about some regiment being stronger than the other, with one army ending up with weaker units' than the other?

[Nathan Ross]

I am not sure what your question is about, breaking up the pair or slipping the units in two?

I think you may be slightly misreading the Colonel's original question, Robert!

As I understand it, he is asking why there are two field armies in praesentalis in the eastern empire, each commanded by a magister militum in praesentalis, listed in the Notitia Dignitatum, whereas in the west there is only one. (I think I have that right - if not je m'excuse, mon colonel!)

I don't have an answer for that either, but I suspect the original single eastern praesental army must have been split post-Adrianople - there is no indication that Theodosius had another field army to draw upon c.379, and in fact seems to have had to assemble a new army from scratch for his rather scrappy pacification campaign against the Goths.

Quite possibly the division had some connection with the attempted military coup and subsequent quasi civil war led by Gainas in AD400. If Gainas was trying to establish himself as a military strongman and state protector on the model of Stilicho, it might have suited the more powerful eastern civilian bureaucracy (Anthemius springs to mind) to split the army and prevent one general rising to paramount control. (I continue to believe that the division of military power in the east and its subordination to civilian authority was a major factor in the survival of the east and the fall of the west!)

This would, of course, suggest that the praesental section of the eastern ND list was updated after c.394. This would not, I think, have been impossible, and would not mean that the entirely of the pars orientalis would have been updated too...

Alternatively, the split could have been instituted by Theodosius himself c.382, perhaps with the idea that if one commander was defeated, as Valens had been, there would be another to take his place.

[Mark Hygate]

Is there also not a genuinely practical reason...?

After the original East-West spilt, and leaving aside any internal squabbles, the old Empire border in the West is fairly 'short' - the remainder of the Danube frontier and then the Rhine - it's an 'internal corner' - with all the Western half of the Empire well behind it.

Whereas, in the East, there is: firstly the exact opposite and for a much longer distance; and secondly it's across two continents and crossing the Bosphoros is a non-trivial exercise!

Having 'the' Praesental Army split into two might make perfect sense for just that reason.

[Colonel Chabert]

Thank you for the replies, gentlemen.

My first question was indeed as Nathan Ross understands it. I was asking when and why the Eastern praesental army was divided in two, though rereading my post I can see that this is far from clear!

[Nathan Ross]

the old Empire border in the West is fairly 'short'... Having 'the' Praesental Army split into two might make perfect sense for just that reason.

Hmm, I suppose so - although the Rhine and the upper Danube together is a frontier of around 1250 miles. The lower Danube section in the eastern empire is only about 700 miles. Then there's the eastern frontier to consider as well, of course.

But the Praesental armies were not intended for frontier defence. The magistri militum in Gaul, Illyricum and Oriens had their own armies to handle any defence-in-depth requirements. I suppose you could argue that one of the two praesental armies in the east was for expeditions towards the Danube, and the other towards the east. But if an emperor was mounting such an expedition he'd presumably want to bring all the troops available to him, which would surely mean both armies.

If you add up the troops of the two eastern Magistri Militum in Praesentalis, you get a very similar number of units of various sorts as the central (Italian) command of the single western Magister Peditum. That implies that the two eastern armies were originally one army, the same size as the western one.

[Mark Hygate]

Hi Nathan,

Indeed - and I agree with all of that. 'Short' is a relative term most certainly!

I wasn't arguing for the Praesental/Central Field Armies being meant for the apparent Frontier defence that the 'local' ones were now for (taking over the role from the 'old' Legions, which now seem to have been more static, but may quite possibly have still maintained their named Field Army legiones/detachments).

However, the Emperor being able to get just himself and staff to and fro over the Bosphoros, plus simply having at least some sort of reserve closer, does make a lot of sense.

[Nathan Ross]

having at least some sort of reserve closer, does make a lot of sense.

Possibly, yes. Although we should bear in mind the point in the OP about the paranoia of emperors (justified, usually!) - would they really want to leave half their army behind under the command of a powerful subordinate?

And thinking about the apparent splitting up of paired units also mentioned in the OP, it seems possible that the two praesental armies were alway intended to work together, with the two magistri acting as equal subordinates to the emperor (or his Praetorian Prefect). This would be a different situation to the west, where a single all-powerful magister could effectively concentrate all military and political power in his own hands.

[Colonel Chabert]

This would, of course, suggest that the praesental section of the eastern ND list was updated after c.394. This would not, I think, have been impossible, and would not mean that the entirely of the pars orientalis would have been updated too...

I think it was Jones who suggested 408 as a possible year for an update of the eastern list on the basis of a post-Stilicho détente. Otherwise I was under the impression most commentators regard the pars orientalis as reflecting the state of affairs in 395 without any later changes. If there were further updates, how would that work? The eastern bureaucracy sends details of its military organization to the west? Why would they do that? Perhaps the information arrived in the West through more "informal" channels, spies or just gossip. Something along the lines of "I say, old chap, my cousin who works in accounts in Constantinople tells me they've created a second Magister Militum Praesentalis. You'd better update your little book."

[Nathan Ross]

I was under the impression most commentators regard the pars orientalis as reflecting the state of affairs in 395 without any later changes.

Yes, the usual idea, of course, is that Theodosius's officials brought the lists west with them after Frigidus, and after that the eastern list was sort of preserved in aspic while the western list was updated sporadically and apparently without much consistency.

However, this runs into questions of what the Notitia Dignitatum was for, who compiled it, and when - which in turn lead to further questions. There was a conference about it last year in Freiburg, which doubtless featurd some illuminating theories, but sadly we'll have to wait quite a while before we get the see the papers...

If there were further updates, how would that work?

Although there was a sort of cold war between the eastern and western courts for nearly 15 years between the deaths of Theodosius and Stilicho, things did warm up a bit after that. There were communications passing between Constantinople and Ravenna in 409, preserved in the Theodosian Code, and in summer 410 the eastern court sent a military force to aid the west (where it apparently remained, and elements of it could have ended up in Spain, as I suggested in this thread).

So the western court must have had a good idea of military dispositions in the east during this period, at least as concerns the field armies. The praesental armies would have been easiest to keep track of, and I would think it quite possible that the western primicerius notariorum might have updated his eastern list to reflect what he knew of recent developments.

Actually that might explain the split in the praesental armies - if the western compiler simply heard that the eastern army had been divided equally between two magistri, he could have gone through the list apportioning one unit to one magister and the next to the other, thereby breaking up the 'linked pairs'...

[Colonel Chabert]

Actually that might explain the split in the praesental armies - if the western compiler simply heard that the eastern army had been divided equally between two magistri, he could have gone through the list apportioning one unit to one magister and the next to the other, thereby breaking up the 'linked pairs'...

Yes, that thought had occurred to me as well. Though typically for the ND even this division isn't clear-cut. While the Auxilia Palatina pairs have all clearly been split in half, the same is not true for the Legio Palatina lists where most of the pairs are intact (in fact all of them except for the Lanciarii/Mattiarii).

[nikgaukroger]

I have a recollection of a suggestion that the 2nd eastern praesental army was formed following the defeat of Magnus Maximus with Theodosius taking some of the western army back east with him.