The ensigns of the Roman army fulfilled an important tactical function: the transfer of commands from the commander; in this case they were accompanied by the sound of the cornu (Veg. Mil. 2,22). Due to their importance, they achieved an almost religious validity (cf. for instance Tac. Ann. 1,39,4). According to tradition, Romulus provided the first legion with animal symbols such as the eagle, the wolf, the horse, the wild boar and the minotaur (Plin. HN 10,16).
At that time, each of the thirty maniples supposedly received a signum (Ov. Fast. 3,115; Plut. Romulus 8)…