Late Roman Unit Sizes

[Nathan Ross]

If We accept that Ammianus was not using classicing terms then he was using Legion, Auxilia, Cohort, Centuries and Maniples as late as possibly 395.

There's the problem that Vegetius (a near contemporary) makes it clear that he is discussing the ways of the 'ancients' when he talks about cohorts and maniples. Also that Ammianus uses quite a few other words that appear archaic (gladius, Parthians) and ends his piece with a statement that he has written in 'the grand style' - by which we could assume the style of older Roman historians. This might indeed suggest the deliberate use of classical archaicisms.