The article examines the events during which the Oirats were involved in the political life of Tibet in the 17th-18th centuries; special attention is paid to the peculiarities of historiographic approaches to some facts. The prominent role played by the Khoshut ruler Güshi Khan in the establishment of the Tibetan theocracy is recognized universally. However, in a 18th century work by cleric Sumpa Khenpo he is actually referred to as a savior of the religion, defender of the faith and reincarnation of the great Buddhist teacher Padmasambhava; the bestowing of the title ‘Dharmaraja’ on Güshi Khan was reported to have been preceded by some airglow around him. A 20th century Tibetan researcher, W. D. Shakabpa, claims that his title of King of Tibet was rather formal, and the position of Khan within the Tibetan community was lower than that of Desi / Diba who acted as the chief administrator - which is illustrated by the place assigned to him at audiences in accordance with special rules based on hierarchy and age. W. D. Shakabpa recognizes his religious zeal and devoted worship of the Dalai Lama, and mentions a fact testifying that before Güshi Khan’s conquest of Tsang the Tibetan hierarch preferred that the Khoshut ruler would return to Kokonor (Qinghai). Though it is usually considered that the Khoshut protectorate over Tibet was established in 1642, the Tibetan scholar mentions that “all political activities were conducted by Desi”. At the same time, W. D. Shakabpa points out the gross mistake introduced in a number of Chinese sources according to which the Mongols have since ancient times been viewed as vassals to the Chinese and, thus, Güshi Khan is erroneously reported to have been a Chinese representative. Under Güshi Khan’s heirs, the role of Khoshut rulers in Tibetan policies decreased dramatically which resulted in an attempt by his descendant, Lhabzang Khan, to seize real power. Tsewang Rabtan, the Khan of Dzungaria, was to become another ‘Güshi Khan’ - a savior of the Buddhist church from the usurper Lhabzang - and gain certain influence on Tibetan rulers. But the international situation had changed over the past decades which determined the historical landscape when Dzungars were invited to settle the internal socio-political crisis. The article analyzes the events during the mentioned crisis in Tibet that resulted in a growth of Manchu political presence.