The division of the Mongol Empire began when Möngke Khan died in 1259 in the siege of Diaoyu Castle with no declared successor, precipitating infighting between members of the Tolui family line for the title of khagan that escalated into the Toluid Civil War. This civil war, along with the Berke–Hulagu war and the subsequent Kaidu–Kublai war, greatly weakened the authority of the great khan over the entirety of the Mongol Empire, and the empire fractured into four khanates: the Golden Horde in Eastern Europe, the Chagatai Khanate in Central Asia, the Ilkhanate in Southwest Asia, and the Yuan dynasty in East Asia based in modern-day Beijing – although the Yuan emperors held the nominal title of khagan of the empire. The four divisions each pursued their own interests and objectives and fell