Leonardo da Vinci sketched a catapult that fired stones using a spring.
His military notebooks contain designs for improved throwing machines, including a large catapult powered by a flexible spring or bow-like mechanism. The stored energy would be released suddenly to propel a projectile from an arm or cup. Leonardo’s interest focused on making siege equipment more powerful, reliable, and mechanically controllable.
A catapult is a broad class of projectile-launching machine, while a ballista uses a tensioned bow and a trebuchet uses a counterweight or traction system. Leonardo’s spring-powered design is therefore best identified as a catapult rather than one of those other machines.
Many of Leonardo’s military drawings were proposals rather than documented battlefield inventions. They reveal his habit of combining observations of existing weapons with experiments in springs, levers, gears, and structural frames. The surviving sketches show engineering analysis, but they do not prove that every pictured machine was constructed.