sentences:  In the ninth month, the Mongols besieged the Jin central capital, Zhongdu (中都; present-day Xicheng and Fengtai districts of Beijing), but were forced to retreat because of Zhongdu's strong defences.In 1212, the Mongols attacked the Jin dynasty and besieged the Jin western capital, Datong Prefecture (大同府; present-day Datong, Shanxi Province).In the same year, Yelü Liuge (耶律留哥), a Khitan, led a rebellion against the Jin dynasty in Jilin Province.