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
Mongol invasions of Vietnam repeatedly ignored demands to attend the Yuan court and offer his personal submission to the Great Khan. By 1266, a standoff developed, as the Emperor Thánh Tông sought a loose tributary relationship, while Kublai demanded full submission. Trần Thánh Tông sent an official letter requiring Kublai to take his darughachi back. Because of civil war in the Mongol Empire, and the Yuan conquest of Song China, armed conflict was delayed. Instead, Kublai reminded him of the peace treaty signed by the Mongols and Đại Việt. As a result of the Mongol conquest of the Song Empire, by 1278–79, Mongol troops