Conquest of Empires: The Jin, the Khwarazmian Shah, and Persia

The Jurchen-ruled Jin dynasty had dominated northern China, including present-day Beijing, since the early twelfth century, and had long treated the Mongols as tribal vassals demanding tribute, a situation that deeply resented Genghis Khan. Mongol refusal to pay homage to the new Jin emperor after 1208 was the formal trigger for war, which began in 1211, when Mongol forces crossed the Great Wall and won a decisive victory at the Battle of Yehuling. Genghis Khan besieged Zhongdu, present-day Beijing, for the first time in 1213-1214; after the Jin court relocated its capital south to Kaifeng, the Mongols resumed the siege, capturing and sacking Zhongdu in 1215. Genghis Khan then delegated the continuation of the war to his general Muqali, who consolidated Mongol control over northern China for nearly a decade (1217-1223) while the khan led the campaign against the Khwarazmian Empire; the final conquest of the Jin was completed under his successor Ogodei, with the fall of Kaifeng in 1233 and the suicide of the last Jin emperor, Aizong, in 1234.