Möngke Khan

Möngke became the fourth khagan of the Mongol Empire on 1 July 1251, the first from the Toluid line. He overhauled imperial administration and pushed the borders wider: his armies took Iraq, Syria, and the Dali Kingdom in what is now Yunnan. On 11 August 1259, he died during a campaign, leaving no designated successor. His two younger brothers, Kublai Khan and Ariq Böke, spent four years fighting for the throne. Kublai won, but the succession struggle and the war with Kaidu that followed fractured the empire permanently.