It is believed that mechanical artillery was invented in 399 BC by Dionysius the Elder, tyrant of Syracuse in Sicily while preparing for war with Carthage. Mechanical artillery was widely used in the ancient world and the Romans probably had the greatest variety of mechanical artillery weapons. With few exceptions, Roman mechanical artillery is noted for being the best of all time and far superior to any that came before or after. Craftsmanship used in the construction of Roman artillery, such as woodworking, was of such high quality that comparable workmanship has rarely been seen anywhere else, even in furniture. The Romans had many different types of mechanical artillery and much of it fell into disuse after the demise of the Roman Empire.
Evidence that mechanical artillery was brought forward from the classical period into the medieval period is lacking. It is known that the Romans used artillery to support their conquests in other parts of Europe. Obviously, the other Europeans would have noted the idea at that time. Evidently, they were unable to acquire examples for reverse engineering. Some historians believe that the medieval period’s mechanical artillery was reinvented independently. With few exceptions, it is known that Classical period siege engines were far superior to their medieval counterparts.
After the decline of the Roman Empire, mechanical artillery became important once again in medieval Europe where new styles of fortifications, specifically castles, brought a resultant surge in siege warfare. This revived the use of mechanical artillery and one particular device, the trebuchet, eventually ended the use of castles as fortifications.