. in 1219 which mongol king attacked trans oxania
Mongol conquest of Khwarezmia During the invasion of Transoxania in 1219, along with the main Mongol force, Genghis Khan used a Chinese specialist catapult unit in battle; they were used again in 1220 in Transoxania. The Chinese may have used the catapults to hurl gunpowder bombs, since they already had them by this time.[14] While Genghis Khan was conquering Transoxania and Persia, several Chinese who were familiar with gunpowder were serving with Genghis's army.[15] Historians have suggested that the Mongol invasion had brought Chinese gunpowder weapons to Central Asia. One of these was the huochong, a Chinese mortar.[16]