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
Mongol Empire the elimination of Batu's own dominance there. In the southern part of the empire, Möngke Khan himself led his army to complete the conquest of China. Military operations were generally successful, but prolonged, so the forces did not withdraw to the north as was customary when the weather turned hot. Disease ravaged the Mongol forces with bloody epidemics, and Möngke died there on 11 August 1259. This event began a new chapter in the history of the Mongols, as again a decision needed to be made on a new great khan. Mongol armies across the empire withdrew from their campaigns