Leonardo da Vinci designed a catapult to hurl stones with a rotating throwing arm.
His military notebooks contain studies of torsion and spring-powered mechanisms for launching projectiles. In a catapult design, stored energy is released through an arm that swings forward and sends a stone or other missile toward a target. Leonardo examined ways to increase power while controlling the machine’s movement and reload process.
The word catapult covers several ancient and medieval siege machines, so Leonardo’s designs should not automatically be labeled a trebuchet or a ballista. A trebuchet uses a counterweight or traction system, while a ballista is a tension-powered projectile weapon with a different form.
Leonardo did not invent siege artillery, which had existed for centuries before him. His contribution was the detailed study and refinement of mechanisms used in military engineering. Many of his proposals remained drawings rather than battlefield-tested machines.