The word cannon comes from the Greek kanun, meaning a tube. One early surviving cannon was an octagonal tube with a round bore. It had a breech block hammered in to place during casting. Cuprum and latten, both forms of brass, were used to make guns. But soon it was clear that cast iron was the best material. At first cannons were either placed on a mount to point them upwards or tied to a wooden board in order to tip the weapon and aim it by placing wedges underneath. In the fifteenth century one finds trunnions (wheeled platforms) in use. Cannons were loaded either by a mobile chamber or thunder-box, or else at the breech. The chamber was filled with gunpowder and a heated touch applied to the hole in the tube or the touch-hole. The chamber was closed with a bung of soft wood to act as a wad between the charge and the shot. The bung would pop out like a cork, the idea being that the chamber itself should not explode. The mobile chamber was placed in the breech and clamped with an iron rod, then packed with tow. By the middle of the fifteenth century some very large cannons were being manufactured.
