The Khoshut Khanate
The Oirats converted to Tibetan Buddhism around 1615, and it was not long before they became involved in the conflict between the Gelug and Karma Kagyu schools. At the request of the Gelug school, in 1637, Güshi Khan, the leader of the Khoshuts in Koko Nor, defeated Choghtu Khong Tayiji, the Khalkha prince who supported the Karma Kagyu school, and conquered Amdo (present-day Qinghai). The unification of Tibet followed in 1641, with Güshi Khan proclaimed Khan of Tibet by the Fifth Dalai Lama. The title "Dalai Lama" itself was bestowed upon the third lama of the Gelug tulku lineage by Altan Khan (not to be confused with the Altan Khans of the Khalkha), and means, in Mongolian, "Ocean of Wisdom."
Amdo, meanwhile, became home to the Khoshuts. In 1717, the Dzungars invaded Tibet and killed Lha-bzang Khan (or Khoshut Khan), a grandson of Güshi Khan and the fourth Khan of Tibet.
In 1723 Lobzang Danjin, another descendant of Güshi Khan, defended Amdo against Qing Dynasty's attempts to extend its rule into Tibet, but was crushed in the following year. Thus, Amdo fell under Chinese domination.