The Ballista



Originally developed in 399 BC. by the ancient Greeks at Syracuse, the ballista was in effect a giant crossbow, used for shooting large arrows or darts. It was a powerful anti-personnel weapon, capable of transfixing several armoured men with a single dart.





A crossbow works by tension in a strong bowstave. Most ballistas used torsion in two skeins of rope or animal sinew. A strong wooden frame carried the two skeins vertically, with the dart resting in a groove in the horizontal stock of the weapon. Two horizontal wooden arms pass through each skein and are linked by a strong bowstring. As the arms are pulled back, the rope is twisted to become a powerful spring. Like a large crossbow, the bowstring is pulled back by a winch and retained by a rotating trigger or nut.





Ballistas were typically used for defence against besieging infantry. For shelter, they were often situated in a wooden shelter or hoarding. Their mounting allowed them to be swivelled to bear against the advancing troops, but they weren't capable of rapid traversing.





The ballista dart in flight (it's the horizontal line, just in front of the trébuchet's beam).

The dart fired by a ballista is a wooden shaft, around five feet long. Brass flights keep the flight straight and an iron head penetrates armour.