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
Nayan (Mongol Prince) support Nayan's rebellion, Kaidu remained a potent threat for the remainder of Kublai Khan's life. Kublai chose not to regard Nayan's Nestorian Christian co-religionists as guilty by association, and refused to allow them to suffer any level of persecution within his lands. In the wake of the suppression of Nayan's rebellion, Kublai Khan was able to begin to fully incorporate the lands and peoples previously dominated by the appanage princes into his domain. Nayan (Mongol Prince) Nayan was a prince of the Borjigin royal family of the Mongol Empire. He raised a noteworthy and serious rebellion against the Mongolian Khagan,