It was a defensive war machine invented by Archimedes to face Roman ships in the siege of Syracuse. It consisted of an articulated beam based on a rotating vertical pillar or platform. At one end of the beam was a
counterweight and at the other end a load was suspended by rope (for example, a large stone or a lead weight). When not used, the machine was laid alongside the wall in a horizontal position (so as not to be visible from the sea), wound and secured by rope and a manual winch (for balancing the counterweight). When a ship approached the wall, the operators released the winch so that the end would gradually ascend enabling the load to pass over the wall by rotating the balance vertical pillar (via horizontal hand levers). When the load was above the ship, the rope was cut so that it would fall onto the target with great force. According to ancient writers, the war machines of Archimedes were so effective that even when a simple beam emerged from the walls, the Romans retreated in panic.