The End of the Primus Pilus

[Robert Vermaat]

Do we have any idea what the earliest dated use of these new ranks might be?

Reference begins in the 320s and becomes universal soon after. This continues until after Justinian's reign, when most Latin names are translated into Greek. (Rance, Philip (2007b): Campidoctores Vicarii vel Tribuni: The Senior Regimental Officers of the Late Roman Army and the Rise of the Campidoctor, in: Ariel S. Lewin and Pietra Pellegrini (eds.) (2007): The Late Roman Army in the Near East from Diocletian to the Arab Conquest, p. 396-7)

I remember some controversy about primicerius, I think - was it usually a civil rather than military rank, or confined to certain units, or something?

Primicerius is, with tribunus, vicarius and campidoctor, one of the few mentioned in both old as well as new styled units. I'm not sure where it originated.