Around 850 A.D. gunpowder was invented by the Chinese. The Chinese mostly used it for fireworks in the 1200's. No one is for sure how gunpowder got to Europe. Some think Europe invented it on there own and others think it traveled from China. Gunpowder is thought to be first used in the Battle of Crecy in 1346 A.D. Gunpowder changed how war was played. Kingdoms could no longer defend against cannons and firearms, so knights were soon replaced by foot soldiers with firearms. Then during 1600's and 1700's William Congreve made rockets for wars. Then late in the 17th century the gun was invented. This caused a huge change in all future wars. War could of been won/lost and it could of changed history if it was invented earlier! The possibilities are endless!