Genghis Khan (c. 1167 – August 18, 1227) was a Mongolian ruler who became one of the world's most powerful military leaders, who joined with the Mongol tribes and started the Mongol Empire. He was a Mongol Emperor who was very successful in battles, conquering many other peoples such as the Jin Dynasty. He was a very strong and powerful emperor who occupied much of China and some surrounding countries of China. His children and his grandchildren started the largest empire in the world.. Genghis Khan's grandson, Kublai Khan, was the first ever emperor of the Yuan Dynasty (1271–1368) in China.