01-06-2013, 07:56 PM
Quote:We must bear in mind that in republican times previous to the the first century B.C half or more than half the strength of a consular army was composed of allied cohorts with each of them having a single commander, idem with the imperial era auxiliary cohorts and alae. If this was deemed necessary for these units to operate efficiently in combat and in campaign, why should it be different for the legionary cohorts? After all the allied cohorts fighted in the same way than the legionary ones in the same battleline and in the same battlefields.
This is true. But did every auxilia really need a commander on the battlefield? Or did they need a commander, when in a separate camp in peacetime (defensive role, small independent campaigns)? Like a legion camp with 10 cohors had the Legate and his staff officers for daily business and could always appoint a praepositus cohortis/vexillationis if needed. The auxilia was often hundred miles away from the legate and therfore needed its own commander.
Look at the cavalry. Let's say you have 4 alae in total in your army and therefore 4 praefects/tribunes. Worst case you can do it with just 2 cavalry commanders on the battlefield: left wing and right wing. Not very realistic, but the question is, did the romans cluster cohorts on the battlefield under the command of tribunes, acting from behind the lines with at least a chance to communicate with the army commander?
However, your rotation idea is not so bad. A lot of historians argue, that all centurions of cohors II-X were of the same rank, because there is no evidence, that the pilus prior had any different role or salary than the 5 others. As I mentioned above, in the auxlia the "pilus prior", here named centurio princeps, had a different role and title than the other five.
You are also right, if you advise to look back to the republic. The imperial legion, is in many ways a republican fossil. The progress in terms of command structure was done with the auxilia, while the legion remained rather traditional. Augustus did not like the idea to touch republican traditions. That was Gallienus job finally.
Ut desint vires, tamen est laudanda voluntas