From the descriptions of decimation it seems kohorts were divided into units of 10, and one was chosen to be killed by the others. Would the officers including the centurio also be distributed to these groups? What about higher officers? Which rank would be sufficient to be above decimation?
Hey,
Decimation seems to have been practiced during early and late republic, and early empire.
During some time in the middle republic, there are no records of it being used, and some scholars think it could be the result of some laws giving rights to the army, laws that where removed by Sulla during late republic. Polybius gives us some information about decimations during early republic. He writes that a tribune would select the men to be executed, so that they are a tenth of the punished unit. He also mentions that rank and guilt did not matter in the selection process. The unit could be a century, a cohort or a larger unit.
According to Appian, during the third servile war (the Spartacus one, late republic), Crassus went so far as to decimate two legions, with their officers included. Mark Antony also did something similar with his defeated legions in Parthia, but only executed a bunch of men, not a tenth of them.
There is no complete record of any of these processes, so it’s impossible to know who exactly died and who didn’t, but, if we go by Polybius, it seems like rank did not matter, so optiones, siniferes, centurions, even a primus pilus, should have been included for posible death, if their cohort was punished.
It’s worth noticing, nevertheless, that officers where highly capable veterans, difficult to replace. This is inference, but it wouldn’t make a lot of sense to execute them, unless they took active part on the crime.
I hope this helps. If you want to read more about it, I found this very good article on the matter of decimations: