Trebuchet

The traction trebuchet Before the famous counterweight machines of medieval castles came the traction trebuchet, a long throwing arm hauled down by a crew pulling on ropes. Its first recorded use is in ancient China, probably by the Mohists as early as the 4th century BCE, with descriptions in the Mozi. It is the clearest military handoff here. By the 6th and 7th centuries, Byzantines, Persians, Arabs and Avars had all adopted it, and whatever the exact route, it was in the eastern Mediterranean by the late 6th century: the Avars and Slavs used traction trebuchets against Thessaloniki in 586. Arab armies took it up in the second half of the 7th century. The later counterweight version has no agreed birthplace, so it is a separate story.