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 the mangonel (or traction trebuchet) was a torsion siege engine which used the tension effect of twisted cords to shoot projectiles, and is considered by some to have been in use until the arrival of gunpowder artillery. Instead, the mangonel operated on manpower-pulling cords attached to a lever and sling to launch projectiles.^[2]

Evidence for the usage of torsion siege weapons such as the onager exist only up until the 6th century, when they were superseded by traction artillery (with the exception of the springald).^[3][4]

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."^[5]