Roman soldiers using two forms of battering ram against the walls of a fortress. A, in the foreground, is the simple form resting on the men's shoulders, while the one at B is hung on a chain hanging from a frame, so enabling the men to concentrate their strength on thrusting the battering ram forward. From Poliorceticon sive de machinis tormentis telis by Justus Lipsius (Joost Lips) (Antwerp, 1605). Engraving.