Among the most common were the ballista, mangonel and trebuchet. The first is the traction trebuchet, or mangonel, which uses manpower to swing the arm. Both the traction and counterweight trebuchets have been called "mangonel" at one point or another. Terminology and definition of the "mangonel" is confused. During these attempts, Wang Dechen was killed by a Song mangonel. He surveyed the approaches, and planted a mangonel at the southeast corner. Onagers have been called onager mangonels and traction trebuchets called "beam-sling mangonel machines". The mangonel is thought to have originated in ancient China. The mangonel is called "al-manjaniq" in Arabic.