Roman Army of Aetius at Chalons

[Flavivs Aetivs]

I think the Ripurian Franks were named after the Ripenses and Riparienses Limitanei grades. My paper offers new theories, it does not assert them as absolutely correct. I just think it is more likely that the Ripuriani are Riparienses, not Ripurian Franks who seem to have fought on Attila's side (Franks of the Neccar River) according to other sources (Sidonius, who is considerably more reliable than Jordanes having lived during the time of the battle). I am saying the Limitanei and field troops were ordered to retreat ahead of Attila and join up with the rest of the Roman forces in Arles, where Aetius was bringing troops from over the Alpes (probably pseudocomitatenses).

However, there were towns in Italy garrisoned, because in 442 in the Nov. Val. its recorded that troops had to be recalled to the defense of Italy against Vandal raiders, as well as a reinstatement of the right to bear arms. I state that these towns were garrisoned by Praesental, not Limitanei, troops.

You are right that the forces in Noricum probably did not participate, as I said it is highly unlikely. Its more likely that they may have been used to block the fords and bridges on the Danube to hinder Attila's crossing in 452.

The Olibrones I think were probably entirely Bucellarii (soldiers on Aetius' personal payroll.) Sidonius Apollinaris records his personal Bucellarii outnumbered the Roman troops (breaking Roman Law) so its likely that some Roman troops were transferred to his direct command/payroll, rather than the Government payroll.

However its also likely that Sidonius is exaggerating somewhat, so I'd argue that Aetius Bucellarii made up a significant portion of the Gallic Army.

Its possible that both armies were so weak that the Praesental and Gallic army were just lumped together into a single "Excercitus Romanus".

[Diocle]

May I ask why you state that the italian towns were garrisoned by 'Praesentales' troops? I mean, Praesentales troops were the top ranking units among the Comitatenses, so we should have few names about what kind of Praesentales units were available to Aetius, in Italy, in 451 AD.
Robert was right writing that, after Frigidus, Theodosius withdrew the Elites of the Palatine/Comitatenses forces from the West, bringing them in the Pars Orientis, to prevent usurpations, so .... what Palatinae/Praesentales units or Vexillationes were still present in Italy at the time of Aetius?

[Flavivs Aetivs]

The Praesental Army was still present - most of the best units in the west are recorded in the Notitia Dignitatum, the Cornuti, Brachati, etc.

The Praesental and Gallic army probably had been heavily mixed by this point, having operated together so much.

Its impossible to say what Roman troops were at Chalons. My best guess would be the remaining Palatine and Comitatenses units of the Praesental Army had been combined into the Gallic Army, and now there was a single Roman Army with Limitanei units guarding passes and towns.


EDIT:
There is another possibility: Sidonius Apollinaris writes that Aetius' Bucellarii outnumbered the Roman Troops in the mid 5th century. If Sidonius' Apollinaris statement of "few and sparse auxiliaries without one Roman soldier" can be interpreted a different way, it may mean that Aetius, who may have incorporated some of the Palatina units into his Bucellarius, was leading his personal army out of Italy, but it was not comprised predominately of Roman troops.