Although the Song dynasty was able to hold back the Jin, a new foe came to power over the steppe, deserts, and plains north of the Jin dynasty. The Mongols, led by Genghis Khan (r. 1206–1227), initially invaded the Jin dynasty in 1205 and 1209, engaging in large raids across its borders, and in 1211 an enormous Mongol army was assembled to invade the Jin. The Jin dynasty was forced to submit and pay tribute to the Mongols as vassals; when the Jin suddenly moved their capital city from Beijing to Kaifeng, the Mongols saw this as a revolt. Under the leadership of Ögedei Khan (r.1229–1241), both the Jin dynasty and Western Xia dynasty were conquered by Mongol forces in 1233/34.