Drogön Chogyal Phagpa (; ; 1235 – 15 December 1280), was the fifth leader of the Sakya school of Tibetan Buddhism. He was also the first Imperial Preceptor of the Yuan dynasty, and was concurrently named the director of the Bureau of Buddhist and Tibetan Affairs, serving during the reign of Kublai Khan. Historical tradition remembers him as the first vice-ruler of Tibet under the Yuan emperor as well as one of the Five Sakya patriarchs (). Although this is historically disputed, he played a very important political role. Early life Phagpa was born in Ngari (West Tibet) in 1235 as the son of Sönam Gyeltsen (, 1184–1239), a member of the Khon family () which held hereditary power over the Sakya Monastery in the Tsang region, and his mother was Kunga Kyi (). The Red annals name his mother as Jomo Konchog Kyi. He was the nephew of Sakya Pandita (1182-1251), who began the relationship between Sakya and the Mongol conquerors after their first invasion of Tibet in 1240. In 1244, Sakya Pandita left Sakya in order to visit the royal camp of Godan Khan, son of Ögedei Khan, to act as intermediary between the Mongols and Tibetans. He brought with him his young nephews, the ten years-old Phagpa and his brother, the six years-old Chakna Dorje. On the way, they stopped in Lhasa, where Phagpa took the vows of a śrāmaṇera at the Jokhang in front of the statue of the Jowo offered by the Princess Wencheng, the Chinese wife of Songtsen Gampo. Sakya Pandita preached sermons along his way and arrived at Godan's camp in Liangzhou in 1247, where Mongol troops were exterminating Han Chinese by throwing them in a river. Sakya Pandita, horrified, gave religious instructions, in particular stressing that killing a sentient being is one of the worst acts according to Buddhism. He gave religious instruction to the prince and greatly impressed the court with his personality and powerful teachings. He is also said to have cured Godan of a serious illness. In return, Drogon Chogyel Phagpa was supposedly given "temporal authority over the 13 myriarchies [Trikor Chuksum] of Central Tibet." Since the myriarchies had not yet emerged as a territorial unit, this cannot be entirely correct. Tibetan historians quote a letter that Sakya Pandita wrote to the local leaders of Tibet in 1249 where he stated that they henceforth must carry out the administration