The Onager

The onager, a form of catapult that used torsional force produced by a twisted rope or springs to generate the potential energy needed for the shot, was named after the wild ass because of its kick. The first person to mention it was the historian Ammianus, who compared the weapon to a scorpion.

In addition to the aforementioned artillery systems that could utilize boulders to damage walls and small fortresses, the Romans also started to use ballistae, which were primarily used for assaulting enemy troops with bolts (as was discussed above). The Romans utilized rocks and flammable substances as projectiles, firing them at their enemies. The Romans won many battles thanks to this military strategy.