Diocletian: legions and rank structure

[Nathan Ross]

The use of the term ordinario for centurion seems 4th century, not third and Hepworth is contending that Legio II Ital Div is based on the Rhine in the 250s.

Not a common view, I think. Ordinarius does seem to be tetrarchic at the earliest; none of the handful of centurio ordinarius inscriptions are explicitly dated, but seem to have an early 4th century pagan focus.

In fairness to Hepworth, he was perhaps one of the first English-language scholars to study much of this material, and clearly a lot of his views are hypothetical. Nowadays we tend to have different hypotheses, but it's always possible that we're not correct either!

Sylvian Janniard, in Centuriones ordinarii et ducenarii dans l'armee romaine tardive, believes, for example, that the late Roman army was 'decimalised' (following the rank structures alluded to on the Aurelius Gauis inscription). He says (in my own very approx translation): 'Beginning at the start of the 3rd century, certain centurions were designated by the term ordinarius/atus. In the context of tactical evolution, it is strongly probable that the new name reflected a change in their function, that is to say the command of the lines of battle (ordines). Perhaps this relates to a reintroduction of the manipular order [and the word ordinarius] was an informal equivalent to the lines of the principes and hastati.'

Janniard further suggests that ducenarius was the informal term (in 'sermo castrensis', or camp Latin) for a first cohort centurion commanding a double century of 200 men.

Needless to say, I don't agree with any of this (I don't think legions were decimalised, and I don't think double strength first cohorts survived the 3rd century). But it goes to show the range of possible opinions available!

I'd like to get your thoughts on him and the other members of that vexillation. I think Cowan said that cohorts VI & VII are attested in Italy during this time.

Ross Cowan was writing in the limited format of an Osprey book, so had to go with the most plausible option - I've heard him suggest that actually II It Divitensium might have been a former Maximianic unit fighting for Maxentius in a rearguard action in the Apennines! We don't know, incidentally, that Baudio was commanding the legion, although it does seem overly coincidental otherwise.

But we're probably looking at Constantine's men here, and they probably came from Divitia on the Rhine. Cohorts VI and VII appear on the tombstones, given in the place where more usually the centurion's name would appear. One man (AE 1882, 258) was apparently recruited five years before in Raetia - indicating either that Constantine controlled that province, or that the man was perhaps a former Maxentian soldier drafted into the legion after the battles in northern Italy.

There was an older unit called Divitiensium though, the numerus exploratorum Germanicianorum Divitiensium, who were based in Germania Superior in the third century. One of their inscriptions gives them the title Alexandrianorum, so presumably dating to Alexander Severus. Whether this unit came from some other place called Divitia (possible), or the same place, but before the building of the Constantinian fortification, is unclear.

There's also the numerus Dalmatarum Divitensium that appears on two tombstones from Turin - which Ross Cowan suggests as Maxentian casualties. Flavius Felix signifer de numero Divitensium... civis Am/bianensis turns up on a tombstone from Serdica - perhaps the same unit operating elsewhere in the 4th century, but note the man comes from Amiens!