Khubilai's Succession Struggle and the Empire's Division

Key Insight

While Hulegu achieved major victories in the West, Khubilai faced slow progress in his eastern campaign against the Sung dynasty, compounded by sectarian violence between Taoist and Buddhist monks within his administration. Mongke Khan, dissatisfied with Khubilai's lack of military success and evidence of fraud in his administration, launched investigations, executed officials, stripped Khubilai of financial prerogatives, and summoned him to Karakorum. Khubilai submitted, was publicly forgiven, but this did not resolve the underlying tensions or advance the Sung conquest, leading Mongke to decide he would personally lead the campaign.

Mongke's death on August 11, 1259, during the Sung campaign, triggered a succession crisis and halted the empire's advancement. Instead of uniting for an election, various factions, particularly Hulegu in the Middle East and the Golden Horde in Russia, secured their territorial gains. Khubilai, after Mongke's death, turned his focus from the Sung to challenge his youngest brother, Arik Boke, who administered Karakorum. Both brothers summoned separate khuriltais: Arik Boke, seen as a traditionalist 'Prince of the Hearth,' held his in Mongolia with support from most of the Golden Family and Mongke's widow, proclaiming himself Great Khan in June 1260.

Khubilai, influenced by his Chinese ministers, staged a coup d'état by holding his own khuriltai in his territory, proclaiming himself Great Khan and concurrently Emperor (Zhongtong) in 1260. He leveraged his control over the Chinese army and, crucially, the food supply to Karakorum, which had become too large to sustain itself locally. By cutting off food, Khubilai starved Karakorum into submission, eventually defeating Arik Boke after several battles, though Arik Boke temporarily retook Karakorum in 1261. The harsh winter of 1263 and animal famine (zud) weakened Arik Boke's forces, forcing his surrender to Khubilai in 1264. Khubilai publicly shamed Arik Boke, leading to family complaints, and although publicly pardoned, Arik Boke mysteriously died in 1266, likely poisoned. Khubilai became Great Khan, but the empire formally divided into four primary administrative zones: Khubilai's China, the Golden Horde, Hulegu's Ilkhanate, and the central steppes (Moghulistan), marking the end of a unified Mongol Empire.