Imaginiferi (1st/2nd c AD)

[Praefectusclassis]

We also may need to consider that Tacitus may not have used the precise military terminology, especially considering that there is no definitive proof that he himself had military experience.

That's an often heard accusation, but not necessarily correct. I believe there's an article about exactly this subject in the conference proceedings La Hierarchie (Rangordnung) de l'armee Romaine, and see also Saddington, D. B., "Tacitus and the Roman Army," Aufstieg und Niedergang der römischen Welt II. 33.5 (Berlin/NY 1991) 3484-3555.[/i]