Güshi Khan
Sonam Choephel (1595–1657 CE), the first regent of the fifth Dalai Lama, was "the prime architect of the Gelug's rise to power". Sonam Choephel requested the aid of Güshi Khan, a powerful Dzungar military leader to end decades of clan-wars in Dbus and Gtsang provinces, and the Tibetan civil war of 1639–1642. Güshi Khan (who was head of the Khoshut tribe) conquered Kham in 1640 bringing the Sakyas and the lords of Kham and Amdo under their control. His victory over Karma Tenkyong, the prince of Tsang in Shigatse, in 1642, completed the military unification of the country and the establishment of the Khoshut Khanate. By this feat the Phagmodrupa Dynasty, which was associated with a variant of the Kagyu school, was technically replaced; in fact it had been powerless for many years. By subsequently formally recognizing the Fifth Dalai Lama's authority in 1642, Güshi Khan effectively made Gyatso the temporal ruler of all Tibet.