Death of Möngke Khan at the Diaoyu Fortress Front

Timeline

1. 1258–1259Diaoyu Fortress · SichuanAfter accession, Möngke Khan continued the expansion policy, ordering the princes to attack the Song along separate routes in 1258. Möngke personally led the central army into Sichuan, taking up positions outside Diaoyu Fortress in February 1259, and launched a prolonged siege of this stronghold commanding the Jialing River passes; Southern Song defenders Wang Jian and others led troops and civilians in stubborn resistance.
2. c. 1259Diaoyu Fortress · SichuanUnder the harsh conditions of a prolonged siege combined with intense heat and epidemic disease, Möngke Khan died of illness in the Mongol camp at Diaoyu Fortress. The Yuan-compiled History of Song records that he died in the army; later historians have endlessly debated the cause of death and exact date, but Möngke's death was undoubtedly the turning point of this southern campaign.
3. 1259–1260Mongol Empire · ChinaAfter news of Möngke Khan's death spread, the various Mongol armies successively returned north. Kublai, forced to negotiate peace with the Southern Song and withdraw at the Ezhou front, marched back to contest the khanate; his brother Ariq Böke also proclaimed himself Great Khan on the steppe, plunging the empire into a divided civil war. The Southern Song gained strategic respite from Möngke's death, and the Mongol-Song War entered a new phase.