Mongols Destroy Jin

In late Jin, politics were corrupt, national strength was weak, and the Mongols attacked constantly. From 1211 Genghis Khan repeatedly campaigned south against Jin, defeating the main Jin army at Yehuling and elsewhere and besieging the Central Capital (present-day Beijing). In 1214 Jin was forced to move its capital to Nanjing (present-day Kaifeng, Henan), and the next year the Mongols took the Central Capital, and Jin lost large areas north of the Yellow River. In 1229 Genghis Khan's third son Ogedei succeeded as great khan and continued the attack on Jin. In 1231 the Mongol army advanced in three columns, one under Tolui passing through Southern Song's Hanzhong region to circle behind Jin. In 1232 Tolui defeated the main Jin army at Sanfengshan in Junzhou, destroying Jin's elite forces. The Mongols then besieged Bianjing, Emperor Aizong of Jin fled and finally reached Caizhou (present-day Runan, Henan). In 1233 Southern Song allied with the Mongols, agreeing to destroy Jin together and to return the Henan lands to Song afterward. Southern Song sent Meng Gong with grain to join the Mongols in besieging Caizhou. In early 1234 the Mongol–Song armies broke Caizhou; Emperor Aizong passed the throne to the last emperor, Wanyan Chenglin, and hanged himself, and Jin fell after 120 years. After Jin's fall Southern Song tried to take back the old Northern Song capitals, sending troops into Kaifeng, Luoyang and elsewhere, but was counterattacked by the Mongols and failed, the “Duanping Entry into Luoyang”. From then on Southern Song and the Mongols faced each other directly and Mongol armies attacked Southern Song.