Coins in medieval Europe were always struck using iron dies. The design would be punched or engraved into the dies back to front, so that it would be the right way round on the coin. The lower die (the pile), would be mounted in a wooden block, and a blank piece of metal placed on top. The upper die (the trussel), would be struck with a hammer, pressing the design into the blank. The trussel has a slightly mushroom-shaped top as a result of being struck with the hammer, and the pile has a spike to mount it in the block. These matching dies date from the 1350s, in the reign of Edward III of England (1327-77). The upper die has the design for the back of the coin, and shows that the die was used at Durham. These dies are part of a larger group found in Westminster Abbey. Many of the dies are worn, and others have blank faces. This suggests that they were sent to London to be re-cut when they wore out. The coin shows what a coin from these dies would have looked like, although it was struck from different dies of the same type.