Mongol Southern Campaign in Yunnan

Timeline

1. 1240–1243Southwestern frontier of the Mongol Empire · ChinaWhile attacking Shu, the Mongols gradually turned their gaze toward the Dali Kingdom, successor to Nanzhao. Controlling Yunnan could open a flanking route to encircle the Southern Song's southwest and yield warhorses and supplies. In the early 1240s the Mongols began gathering intelligence on Yunnan and probing activities along the border.
2. 1244Dali · YunnanIn 1244 the Mongol court sent envoys to Dali demanding passage for Mongol armies to move south against Song. Dali ruler Duan Xiangxing and the powerful minister Gao Xiang refused and killed the Mongol envoys. This enraged the Mongols and became the direct trigger for the later large-scale southern campaign.
3. 1245–1249Northern Yunnan border · YunnanAfter the envoy incident, Mongol-Dali relations broke down. In the later 1240s the Mongols massed forces in western Sichuan, pressured the northern Yunnan border, and began preparing a larger southern campaign. Though Dali held defensible terrain, it now faced an unprecedented Mongol military threat.