Torsion mangonel myth

A bucket onager, torsion artillery often mistaken for a medieval mangonel

A sling onager, a 4th-6th century torsion weapon

A wheeled whirlwind traction trebuchet from the Wujing Zongyao

A reconstruction of a whirlwind traction trebuchet

The torsion mangonel myth, or simply the myth of the mangonel,^[1] is the belief that mangonels were torsion siege engines such as the ballista or onager which used the tension effect of twisted cords to shoot projectiles. Despite a significant body of research dating as far back as the 19th century pointing to the contrary, "it has not stopped the transmission of the myth to the present day."^[2] Evidence for the usage of torsion siege weapons, with the exception of the springald, exist only up until the 6th century, when they were superseded by the traction trebuchet, more commonly known as the mangonel.^[3][4]