Barbarization?

[Nathan Ross]

Assuming there were not a million of available non-Roman soldiers available, the logic of numbers and availability tells me that the Roman army was not already full of non-Romans

That is pretty good logic, and hard to dispute!

Alaric himself... could have gone all the way to the top.

He did, didn't he? - or close to it at least. Wasn't he appointed Magister Militum for Illyricum by Arcadius? Much of political history c395-408 seems to involve the rival courts of east and west trying to manage and/or utilise the ambitions and demands of Alaric though (and vice versa), so he can hardly be taken as a normal 'barbarian'!

the army was not open to any non-Roman. Another reason to reject the hypothesis of a ‘barbarian Roman army by 400’.

I'm not sure about your first point - we see in the Ambrose quote in my original post that certain Goths were awarded citizenship upon enlistment, and even promoted (directly?) to command positions. This had probably been going on since the mid 4th century at least.

The second point is probably fair though - I was going for a deliberately exaggerated hypothesis to see where it might lead...

However, I do still wonder whether we might see the distinction between Romans and Barbarians in the military sphere breaking down over the course of the later 4th and early 5th centuries. Or, rather, that the late Roman army had, by around 400, acquired a sort of 'corporate identity' that might bring a Roman soldier a lot closer in culture and general outlook to a warrior of the foederati than to a civilian citizen of the empire. Again, this is drawing on Vedran Bileta's paper in the OP - but it would help to explain the transition between Roman and non-Roman rule over the course of the 5th century as a change of orientation rather than a violent destruction or military disintegration.

Who guarded the cities? Surely not citizens and farmers?

I don't see why not, actually! Rome itself appears to have been undefended by regular troops, as we discussed elsewhere. With strong enough walls, even a peasant militia can defend a town against a plundering enemy without siege equipment or the will to conduct a long blockade.

However, there probably were garrisons left in Gaul, just as there were in the towns of north Italy. There just don't seem to have been enough of them, or with sufficient overall command, until the advent of Constantine III, to do anything about the barbarians roaming the landscape...

archaeology... does not show a layer of destruction around this period. Which would be the case if you assume that the Rhine was undefended, the federates overwhelmed, an enemy roaming through all the provinces looking for food and the cities undefended... So I’m thinking hyperbole.

This is all true. And we can certainly read hyperbole into many of those accounts - we know from the news today that not everything written down is necessarily strictly accurate!

But doesn't the 'no destruction' argument also count against a defended Rhine? Defended in the usual way anyway, with forts etc - what happened to the troops? Why didn't they resist? Did the Vandals etc just bypass them, or what? If they did resist, and failed, why don't we see evidence of fighting?

If, on the other hand, Stilicho or somebody else had already entrusted allied Franks with frontier defence, and the Franks did not defend the forts but tried to fight in the open (and were defeated, as Orosius suggests), then we would see no obvious destruction evidence.

As for the cities - unless we discount the idea of a barbarian invasion altogether, the barbarians were clearly living on something. The food supplies were (probably) in the cities, and the cities show no signs of damage. So what happened?

My counter hypothesis: the remaining garrisons and civilian population of Gaul paid the barbarians invaders in food supplies in return for the barbarians not attacking their cities and moving onwards. The Romans knew there were no imperial forces that could save them, so preferred to do deals with the enemy to ensure their survival.

Constantine III, when he turned up with his British troops, preferred to continue to same process and enroll the barbarians in his army, setting part of them to guard the Rhine against further incursions (which explains why Mainz was in the hands of the Alans and Burgundians several years later) and using the rest to defeat Honorius's general Sarus and invade Spain.

All this, of course, was shocking and incomprehensible to the churchmen and moralists of the empire, who preferred to believe that Gaul had gone down fighting in a torrent of fire and blood!

Well... maybe...