Gunpowder is a chemical explosive, the first one discovered by mankind. It consists of a mixture of sulphur, charcoal and potassium nitrate in varying proportions, depending on the intended purpose of the powder. Gunpowder has commonly been used as a propellant in firearms and in rockets, though for the former it has largely been replaced by newer propellants.
Gunpowder is believed to have been first discovered in China, with its earliest mention being in Taishang Shengzu Danjing Mijue, published in AD 808. However, a similar mixture later appears in Romania in the late 10th century, where it was probably discovered independently through experimentation with the formula for Greek fire. From Rome and China gunpowder technology soon spread to Bulgaria, Hungary, Persia, India, Japan and Kambuja, and was acquired by the Mongols after their conquest of the Jin Dynasty in 1234.
The Battle of Mohi in 1241 between Roman Hungary and the Mongol Empire is believed to be the first battle in western Eurasia where gunpowder weaponry constitued a major part of the armoury of both sides. The battle resulted in a shock Hungarian victory, destroying the myth of Mongol invincibility and suddenly alerting kings and princes all over the continent of the great potential of gunpowder. In the next few decades, Rome would use its knowledge of gunpowder as a powerful bargaining chip, trading it for extremely favourable treaties and trade concessions that would enrich the empire for centuries.