Late Roman Unit Sizes

[Flavivs Aetivs]

@Nathan Ross

I would somewhat disagree. It seems that yes, although the Legions at one point numbered 5000 men a series of detachments to guard frontiers or reinforce the rising field armies of Gallenius and Diocletian resulted in their decline.

V Macedonica (Roughly 43 BC - 613 AD if I am correct) is a prime example. They are still mentioned, in the Notitia, as being headquarted in Oescus. However, they have vexillationes in Aegyptus (The Thebaid - Memphis and Heliopolis if I am correct) and in Syria as part of the field army.

V Macedonica may have numbered 5000 men (not including cavalry), but let's assume they sent a cohort to each of the two cities in Egypt they garrisoned. For all intensive purposes, we'll say that cohort is 500 men.

Legio V Macedonica now numbers 4000 men, with 500 in Memphis and 500 in Heliopolis. Now they send a detachment to Syria: let's say 2000 men for Legion strength. Now they number 5000 men, but it's not 5000 men in one place.

The same thing happens with XI Claudia - the Legion is still based in Durostorum (Silistra) but has a Vexillation in Chersonesos (In the Crimea) and a portion in the Gallic Field Army under the Comes Hispaniae.

I think that's what happened to VI Ferrata: either they were destroyed in a war against the Parthians, or so many Vexillationes were demanded from them and spread out across the frontier that it lost its cohesive identity.