Gravity Catapults - Last Step in the Evolution of Medieval Siege Weapons

Gravity catapults went by many names including blida, couiller, and petrary however, the name most often used to refer to these medieval siege weapons is trebuchets.

The last advance in catapult technology, gravity catapults relied on very heavy weights to launch projectiles. One end of the throwing arm had the weight attached to it. A simple trigger mechanism held the other end of the throwing arm down. It was this end of the throwing arm the projectile was attached to.

Releasing the trigger allowed the force of gravity to push the weighted end of the throwing arm down causing the other end of the throwing arm to rise quickly throwing the projectile great distances. The use of these counterweights (the weighted end of the throwing arm) allowed gravity catapults to throw rocks and other "missiles" great distances with a high degree of accuracy.

As time passed, huge trebuchets were created, much larger than any tension, torsion, or traction catapult. The use of the counterweight as the "power source" also allowed the gravity catapult to operate even when wet.

Gravity catapults were a very formidable weapon however, they were destined to be replaced by another Chinese invention... a mysterious substance that was later named gunpowder.