Crude cannons existed in China from about the 12th century, possibly earlier. One of the first weapons used in Europe was the bombard. They were built in different diameter barrels to fire anything from a small rock to a cast iron ball. By the 16th century cannons began to replace bombards. Casting had greatly improved in Europe after about 1570. In the early 1500s, French cannons were used to break up masses of men in their campaigns in Italy. The Germans had some of the best gunners in Europe and developed cannon that could hit targets at up to . Next, the Swedish under Gustavus Adolphus developed lightweight cannons that could easily move around the battlefield. He used a cast 4-pounder that weighed about and could be pulled by just two horses.