Mongol Empire What is referred to in English as the Mongol Empire was called the "Ikh Mongol Uls" ("ikh": "great", "uls": "state"; Great Mongolian State). In the 1240s, one of Genghis's descendants, Güyük Khan, wrote a letter to Pope Innocent IV which used the preamble "Dalai (great/oceanic) Khagan of the great Mongolian state (ulus)". After the succession war between Kublai Khan and his brother Ariq Böke, Ariq limited Kublai's power to the eastern part of the empire. Kublai officially issued an imperial edict on 18 December 1271 to name the country Great Yuan ("Dai Yuan", or "Dai Ön Ulus") to establish the
Division of the Mongol Empire Division of the Mongol Empire 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 Great Khan that escalated to 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, including the Golden Horde in the northwest, the Chagatai Khanate in the middle, the Ilkhanate