 Complete the following phrase:  About 1620 the western Mongols, known as the Oirats, united in Dzungaria. In 1678, Galdan received from the Dalai Lama the title of Boshogtu Khan, making the Dzungars the leading tribe within the Oirats. The Dzungar rulers used the title of Khong Tayiji, which translates into English as crown prince. Between 1680 and 1688, the Dzungars conquered the Tarim Basin, which is now southern Xinjiang, and defeated the Khalkha Mongols to the east. In 1696, Galdan was defeated by the Qing dynasty and lost Outer Mongolia. In 1717 the Dzungars conquered Tibet, but were driven out a year later by the Qing. In 1755, Qing China took advantage of a Dzungar civil war to conquer Dzungaria and 