Uyghurs
Contemporary scholars consider modern Uyghurs to be the descendants of a number of people, including the ancient Uyghurs of Mongolia who arrived at the Tarim Basin after the fall of the Uyghur Khaganate, Iranic Saka tribes, and other Indo-European peoples who inhabited the Tarim Basin before the arrival of the Turkic Uyghurs. DNA analyses indicate that the peoples of central Asia such as the Uyghurs are all mixed Caucasian and East Asian. Uyghur activists identify with the Tarim mummies, remains of an ancient people who inhabited the region, but research into the genetics of ancient Tarim mummies and their links with modern Uyghurs remains problematic, both to Chinese government officials concerned with ethnic separatism, and to Uyghur activists concerned that the research could affect their people's claim of being indigenous to the region.
History of Xinjiang
Uyghur nationalist historians such as Turghun Almas claim that Uyghurs were distinct and independent from Chinese for 6000 years, and that all non-Uyghur peoples are non-indigenous immigrants to Xinjiang. However, the Han Dynasty (206 BC – 220 AD) established military colonies (tuntian) and commanderies (duhufu) to control Xinjiang from 120 BC, while the Tang dynasty (618–907) also controlled much of Xinjiang until the An Lushan rebellion. Chinese historians refute Uyghur nationalist claims by pointing out the 2,000-year history of Han settlement in Xinjiang, documenting the history of Mongol, Kazakh, Uzbek, Manchu, Hui, Xibo indigenes in Xinjiang, and by emphasizing the relatively late "westward migration" of the Huigu (equated with "Uyghur" by the PRC government) people from Mongolia the 9th century. The name "Uyghur" was associated with a Buddhist people in the Tarim Basin in the 9th century, but completely disappeared by the 15th century, until it was revived by the Soviet Union in the 20th century.