High Imperial Roman army vs Late Roman army

[Timianus]

Although the roman army was low on manpower, they were certainly not replaced with Barbarians. The Gallic Field Army was indeed strong. 22,500 men at Chalons is my estimate for the Gallic Army (based on a 2/3 strength of AHM Jones 34,000 in the ND to compensate for paper strength, wounded, sick, deserters, etc.)

So what happened to it after Chalons? From your other posts, you seem to state that a large part of the Gallic Field Army were personal retainers of Aetius and they just disbanded after he died. Or, am I misunderstanding you?