In the fall of 1213, the Mongols, under the leadership of Genghis Khan, split their forces into three groups to attack the Jin dynasty. They conquered nearly all the prefectures and counties in Hebei; only Zhongdu, Zhending Prefecture (眞定府; around present-day Zhengding County, Hebei Province), Daming Prefecture (大名府; around present-day Daming County, Hebei Province), and 11 other cities did not fall to the Mongols.