The Imperial helmet-type was a type of helmet worn by Roman legionaries. Prior to the Empire, Roman Republican soldiers often provided their own equipment, which was passed down from father to son. Thus a variety of equipment, from different eras was present in the ranks. Even as the professional Imperial Army emerged, and short-term service citizen soldiers became rare, useful equipment was never discarded. So when the improved Imperial helmet appeared, it replaced what remained of the very old Coolus type, which was largely superseded at the time by improved versions of the Montefortino helmet type which continued to serve alongside it for a time. This constituted the final evolutionary stage of the legionary helmet (galea).