Earliest Pivot Weapons

• The trebuchets that were used in the Middle Ages to lay siege to castle and fort walls were one of the earliest weapons to use a pivot. Trebuchets used gravity, consisting of heavy counterweights on the end of a long throwing arm rather than twisted cords. The long arm sat over a pivot point, acting as a two-sided lever. Soldiers loaded one end of the arm with a projectile, then pulled on ropes to lift a massive counterweight on the other end. Locked into position, with the counterweight raised and storing potential energy, a key was pulled to start the downward travel of the arm, which pitched the projectile high in the air.