Leonardo da Vinci designed a trebuchet with a large swinging arm to launch stones.
Leonardo’s military notebooks contain studies of siege engines, including machines that used leverage and a long throwing arm. In a trebuchet, the arm pivots around an axle and accelerates a projectile, commonly using a counterweight or another source of stored energy.
Leonardo was not the inventor of the trebuchet. These engines had been used for centuries before his lifetime, and medieval engineers developed several related designs. His drawings show how Renaissance engineers analyzed established weapons through geometry, proportion, and mechanical refinement.
A trebuchet is often loosely called a catapult, but the terms can describe different mechanisms. A counterweight trebuchet uses gravitational energy, while torsion engines such as the ballista store energy by twisting bundles of material.