Mongol conquest of the Song dynasty Mongol conquest of the Song dynasty The Mongol conquest of the Song dynasty under Kublai Khan (r. 1260–1294) was the final step for the Mongols to rule the whole of China under the Yuan dynasty. It is also considered the Mongol Empire's last great military achievement. Before the Mongol–Jin War escalated, an envoy from the Song dynasty arrived at the court of the Mongols, perhaps to negotiate a united offensive against the Jin dynasty, who the Song had previously fought during the Jin–Song Wars. Although Genghis Khan refused, on his death in 1227 he bequeathed a plan to attack the
Society of the Mongol Empire when the Song dynasty started replacing their copper coinage with paper currency. When the Mongols invaded Song China they started issuing their own Mongolian bills in 1227. This first attempt by the Mongols did not last long because the notes issued expired after several years and were inconsistent throughout the parts of the Mongol Empire that issued them. In 1260, Kublai Khan created the Yuan Mongol's first unified paper currency with notes that did not have any expiration date. To validate the currency, it was made fully exchangeable to silver and gold and was accepted as tax payments. Currency distribution