centurion to tribune ?

[Tiberius Geracius]

I do know that in most cases in the early part of the Empire that Auxillaries were almost always under the comand of a Roman officer. Mostlikly a centurion. It all goes back to class for officers. Petritions were always officers. Equestrians could become officers, but to what extent I dont know. When in doubt you could aways bump off a few higher officers and get promoted htat way. lol