The next weapon to talk about is called a Cannons. Cannons are any launcher that uses gunpowder or explosive to fire a projectile. (http://www.civilwarcannonstech.com/) Cannons were able to move freely around the battel feild. This allowed for troops to easily move them forward for attacks or backwards for retreats. Cannons were invented (http://mysite.du.edu/~jcalvert/tech/cannon.htm#A) in Europe around AD 1225 and the gunpowder for them was invented in 900 AD by a Chinese alchemist.