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 which carved through the Altai mountains. After his enthronement, Ögedei further expanded the road system, ordering the Chagatai Khanate and Golden Horde to link up roads in western parts of the Mongol Empire. Kublai Khan, founder of the Yuan dynasty, built special relays for high officials, as well as ordinary relays, that had hostels. During Kublai's reign, the Yuan communication system consisted of some 1,400 postal stations, which used 50,000 horses, 8,400 oxen, 6,700 mules, 4,000 carts, and 6,000 boats. In Manchuria and southern Siberia, the Mongols still used dogsled relays for the yam. In the Ilkhanate, Ghazan restored the