Gunpowder was used in Europe since the early Renessaince, and used in China before that. It is said that gunpowder was first discovered by some Chinese alchemists who were looking for the elexir of life. They brought three ingredients, saltpeter, sulfur, and charcoal, together and put them over a fire to melt them together. Not smart.
Afterwards, the europeans used gunpowder extensively in the military, and weapons using gunpowder progressed and was at their peak during the American civil war. These weapons included pistols, muskets, cannons and mortars