Roman Army of Aetius at Chalons

[Robert Vermaat]

I try and give some extrapolations of the Roman forces in my article, in which I state Aetius was leading Ripenses and Riparienses (Ripuriani in Jordanes) when Sidonius references his crossing of the Alpes to gather his forces in Arelate. [..] Any limitanei in Gaul were probabaly recalled ahead fo the Hunnic advance to join the Gallic Army. The remnants of the praesental army were likely guarding the Alpes or garrisoned in Italian towns, in the event Aetius was defeated he'd have a second force to harass Attila with.

My guess would be that here you have the Roman limitanei, who are sometimes referred to as Ripenses when guarding a river frontier. Unfortunately the gap between ND and this battle is too large to assume that any of the units mentioned was still in place, but it's not impossible. Especially the Mainz section was reorganized c. 420 and could be in place. Otherwise, we are looking at Ripuarian Franks here (who of course may be those very same units). The limitanei were not recalled to Italy I think (see Procopius). If serving in towns they would havee been in towns in Gaul. Gaul was never abandoned.

It's likely that a significant portion of the Gallic Field Army was also intact, but by this point they were probably no longer on the imperial payroll and were serving out of Loyalty and the prospect of Plunder, along with whatever Aetius could pay them.

Unlikely. The state was short of funds but Aetyius would hardly have been able to pay them. Plus, as I wrote earlier, there was still an 'exercitus Romanorum' after Aetius.

The Olibrones probably account for Aetius' personal Bucellarii, as well as the Palatina and Comitatenses units of the Gallic field army, as the are described as 'once roman soldiers and now the flower of the allied forces.'

I agree up to a point, but to put all those units in one group seem a bit too much. I'd rather think of one (ethnic) group that had until recently fought in the Roman army, not all palatina and comitatenses forces.

However it is also possible that the reason they were undermanned was because they had joined that army, and were sent back to their posts on the Danube. This is still highly unlikely, but if it is we can assume the Cohors Novae Batavorum, the II Lauriacenses and Lanciarii Lauriacenses, and part of I Noricorum joined in the battle. But the odds that they participated are extraordinarily slim.

Extremely unlikely. Noricum is too far off.