Late Roman Army Questions

[Nathan Ross]

what were the differences between the two? I understand it wasn't just roman citizens that could now join the legionary units. So what set them apart?

A good question, and we don't know enough about the process by which these units were formed to answer it clearly.

Officially speaking, as far as I know, citizenship remained a necessity for legionaries - although we see evidence from the later second century that already provincials were being given citizenship on enlistment. Also, after AD212, citizenship was extended to all inhabitants of the empire, making it less of a prized possession. Barbarians settled within the empire (laeti) seem to have been a good source of recruits, as they were obliged to provide military service. Quite possibly many of them ended up in the legions too.

The auxilia, it seems, took both citizens and non-citizens into the ranks (although it's often hard to tell, with many 'barbarians' taking Roman names!). I suspect that they originate with semi-irregular barbarian units ('numeri') in the late 3rd or very early 4th century, who at some point in the 320s (perhaps) were taken officially into the imperial comitatus as bodyguard troops - hence the 'palatina' title. By this point, service in the auxilia was attractive enough to entice citizen recruits as well - the earliest known member of the Cornuti auxilium was a citizen, born in Roman Singidunum, who joined in the 320s (which refutes the idea that the auxilia were all Germanic barbarians!)

As for differences in equipment or training between auxilia and legiones, we really don't know. The auxilia (if we can trust Ammianus) seem to have been more prestigious, exempted from the manual labour that had always been the legionary's lot.

They do seem to have had a different rank structure though (dealt with in the second of the blog posts I linked above), which was not used in the legions - although this too is very unclear!

So much about prestige in the later Roman world hinges on proximity to the emperor(s). Any unit of the comitatus would be close to the person of the emperor, and therefore more prestigious.

Can it be said then that the Foederati took the role of the earlier period auxiliaries?

I'm sure others could answer this one - my knowledge of the later 4th-5th centuries (when foederati as we tend to use the word came to prominence) is rather slight!