Late Roman Army Ranks - Numeri/Limitanei

[Steven James]

By the 4th century, all military units were referred to as numeri, from legions to cavalry vexillationes and scholae. The word meant nothing more than 'unit', (literally 'number', the exact Greek equivalent is arithmos).

So the word did not describe a set number of men. A numerus of auxilia palatina may have been about 500-800 men, a numerus legionum could have been twice that size, and a numerus of limitanei much smaller. There's a note in the Strategikon suggesting that later military units had no set size.

There was an earlier use of numerus, going back to the 2nd century, to describe a (usually) irregular unit commonly stationed in a frontier region. The numeri exploratorum turn up quite early, so they were probably this type of unit. Guessing their size and composition is therefore difficult. 500-800 may be a reasonable assumption, but their numbers may have fluctuated based on the area they had to garrison or patrol.

     

I for sometime tried to follow your outlook that the numerus has no set size, but had to abandon the idea and follow Roman military doctrine that had been practiced since the beginning of the republic. I haven’t found any evidence that the Romans drastically changed their military practices.

 

Just for this example, let’s say a numerus was fixed at 960 infantry, consisting of 800 iuniores and 160 seniores organised into 12 centuries (10 iuniores and 2 seniores) each of 80 infantry. If the 160 seniores are detached, this leaves 800 iuniores consisting of 10 centuries of iuniores. However, what if 2 centuries of iuniores are known as “the reserve” and like at Adrianople, are left to guard the baggage. This leaves 640 iuniores (8 centuries).

 

I have found all Roman units have a fixed size, but the size of the unit changes with the military doctrine being implemented. Most of the varying numbers for legions and units sizes throughout the primary sources are merely indicating a military doctrine being practiced.