Mongol Conquest of the Jin
Also called: Mongol–Jin War, Fall of the Jin
Genghis Khan invaded the Jurchen Jin and overran northern China; Ögedei Khan, allied with the Southern Song, destroyed the Jin in 1234.

Sayf al-Vâhidî. Hérât. Afghanistan · Public domain · Source
In 1211 Genghis Khan invaded the Jin and smashed its main army at Yehuling. After the capital Zhongdu fell in 1215, the Jin moved south to Bianjing (Kaifeng). While Genghis campaigned against Khwarazm, Muqali continued the war in the north; Ögedei defeated the Jin at Sanfengshan in 1232 and, allied with the Song, besieged Caizhou. In the first month of 1234 Emperor Aizong killed himself and the Jin fell. In these years Khitan refugees fleeing the Mongols entered Goryeo, leading to the Battle of Gangdong Fortress.