Möngke Khan

The fourth great khan of the Mongol Empire, Möngke (1209-1259) was the eldest son of Tolui and Sorghaghtani Beki and a grandson of Genghis Khan. His accession in 1251 transferred the imperial title from the line of Ögedei to the Toluid branch of the dynasty, a shift with lasting consequences: from his reign onward, the heirs of Tolui held the great khanate, and from them descended both the Yuan emperors of China and the Ilkhans of Persia.

Möngke earned military standing in the great western campaign of the late 1230s, fighting under his cousin Batu against the Kipchaks and in the Russian principalities. The alliance formed there proved decisive. After the brief reign of Güyük and the regency of Güyük's widow, Batu, the senior prince of the Jochid line, threw his weight behind Möngke's candidacy. A kurultai proclaimed him great khan in 1251, and an alleged plot by Ögedeid and Chagataid princes was answered with a wide purge of those branches, executions and trials that cemented Toluid control but deepened resentments within the family.

As ruler, Möngke worked to restore central authority after a decade of loose regency government. He ordered empire-wide censuses, regularized taxation, curbed the issuing of arbitrary requisition orders by princes, and relied on administrators such as Mahmud Yalavach in the east. He also set in motion the empire's last great coordinated expansion, dispatching his brother Hulagu against the Abbasid caliphate and the powers of southwestern Asia, while his brother Kublai subdued the kingdom of Dali in Yunnan in preparation for war on the Song dynasty. The Franciscan William of Rubruck, who visited the imperial court at Karakorum in 1254, left a detailed account of Möngke's capital and of a religious debate held in his presence.

Möngke took personal command of the Song war and died in August 1259 during the campaign in Sichuan, near the fortress of Diaoyucheng; the precise cause was variously reported. He left no settled succession, and the ensuing contest between his brothers Kublai and Ariq Böke broke the empire's unity for good. Out of that rupture the four great khanates of his grandfather's descendants — the Yuan, the Ilkhanate, the Golden Horde, and the Chagatai ulus — emerged as effectively independent states. Möngke was the last ruler whom all of them acknowledged in fact as well as in name.