Hold your mouse cursor over the trebuchet at the left for a few seconds, to see it in action. The trebuchet was just a long arm with a weight on the end, which was winched to the ground. The weight was attached to the short end of the lever arm. Releasing a pin allowed the weight to fall; this forced the long end of the lever upwards with great speed, pulling a sling that contained the projectile. The sling would increase the effective length of the lever arm, adding even more speed to the projectile before the sling released it. Stones cut especially for use by the trebuchet were sometimes used as the projectile, occasionally weighing as much as 150 kilograms, although the standard weight was more like 30 to 50 kg. The range of the trebuchet was as much as 450 metres, with deadly accuracy. Other projectiles included paving stones, dead animals, pots of quicklime, and scraps of iron. BACK