China’s Southern Song Dynasty had been able to hold back the Jin, but a new and considerable foe had come to power over the steppe, deserts, and plains north of the Jin Dynasty in the person of the Mongols.

Led by Genghis Khan, the Mongols had 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 had been 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 had seen this as a revolt.

Under the leadership of Ögedei Khan, both the Jin Dynasty and Western Xia Dynasty had been conquered by Mongol forces.

The Mongols were at one time allied with the Southern Sung Dynasty, with its capital in Hangzhou, but this alliance had been broken when the Song recaptured the former imperial capitals of Kaifeng, Luoyang, and Chang'an at the collapse of the Jin Dynasty in 1234.

Great Khan Möngke, seeming to take much more seriously the legacy of world conquest he had inherited than had Güyük, concerns himself more with the war in China.