 One of the earliest references to the destructive force of a cannon in China was made by Zhang Xian in 1341, with his verse known as "The Iron Cannon Affair".Zhang wrote that its cannonball could "pierce the heart or belly when it strikes a man or horse, and can even transfix several persons at once".Jiao Yu describes the cannon, called the "eruptor", as a cast bronze device which had an average length of .