The document is about the Mongol conquest of China under Genghis Khan and Kublai Khan. It discusses how the Mongols, originally from Mongolia, expanded their empire throughout Asia and invaded China under Genghis Khan from 1206-1227. In 1264, Kublai Khan established the Yuan dynasty in China with its capital in Beijing. The Yuan dynasty ruled over China for over a century until being overthrown in 1368.