The Toluid Civil War was a war of succession fought between Kublai Khan and his younger brother, Ariq Böke, from 1260 to 1264. Möngke Khan died in 1259 with no declared successor, precipitating infighting between members of the Tolui family line for the title of Great Khan that escalated to a civil war. The Toluid Civil War, and the wars that followed it (such as the Berke–Hulagu war and the Kaidu–Kublai war), weakened the authority of the Great Khan over the Mongol Empire and split the empire into autonomous khanates. Background The Tolui family successfully enthroned their candidate for Great Khan, Möngke, in the kurultais of 1250 and 1251. The Ögedeid candidate for Great Khan, Shiremun, and his cousin Nakhu, were embittered by their loss and plotted a failed assassination of Möngke. Möngke took revenge by purging his opponents in the royal house, and members of both the Chagatai and Ögedei families. Möngke handed control over the Caucasus region to the Golden Horde in 1252. With the approval of Möngke, Berke succeeded his brother, Batu, as Khan of the Golden Horde in Russia in 1255. Hulagu of the Ilkhanate seized control of the Caucasus from the Golden Horde, and his sacking of Baghdad in 1258 angered Berke, a convert to Islam. Möngke Khan died in 1259 without appointing a successor. He probably favored Ariq Böke, whom Möngke designated in 1258 as commander of Karakorum (then capital of the empire), but he did too little else to secure Ariq Böke's claim to the throne. Civil war Kublai Khan was fighting against the southern Song in 1260 when he received news that Ariq Böke was challenging him for the succession of the throne. Ariq Böke formed alliances with powerful members of the Mongol nobility to endorse him as a candidate for Great Khan. Most of Möngke's immediate family supported Ariq Böke including the member of Ögedei, Chagatai and Jochi. Kublai withdrew from the Song and mobilized his troops to fight Ariq Böke. In China, Kublai summoned a kurultai at Kaiping, where he was elected Great Khan. This was the first kurultai to proclaim a Great Khan outside the Mongol homeland or Central Asia. Ariq Böke convened his own kurultai in Karakorum that proclaimed him Great Khan a month later, creating two rival claimants for the throne. Hulagu embarked for Mongolia to attend the kurultai, but the Mamluk defeat of the Mongols at