Legio I Flavia Pacis: one of the legions of the later Roman empire. Its name means "the Flavian legion of peace".
This legion is nothing but a name to us. It belongs to a series that also included II Flavia Virtutis and III Flavia Salutis. The three legions were probably formed by the emperor Constantius II (r.337-361) and fought in the eastern half of the Roman empire.