Қаңқил). Identity Throughout its history, the term Uyghur has had an increasingly expansive definition. Initially signifying only a small coalition of Tiele tribes in northern China, Mongolia and the Altai Mountains, it later denoted citizenship in the Uyghur Khaganate. Finally, it was expanded into an ethnicity whose ancestry originates with the fall of the Uyghur Khaganate in the year 842, causing Uyghur migration from Mongolia into the Tarim Basin. The Uyghurs who moved to the Tarim Basin mixed with the local Tocharians, and converted to the Tocharian religion, and adopted their culture of oasis agriculture. The fluid definition of Uyghur and the diverse ancestry of modern Uyghurs create confusion as to what constitutes true Uyghur ethnography and ethnogenesis. Contemporary scholars consider modern Uyghurs to be the descendants of a number of peoples, including the ancient Uyghurs of Mongolia migrating into the Tarim Basin after the fall of the Uyghur Khaganate, Iranic Saka tribes and other Indo-European peoples inhabiting the Tarim Basin before the arrival of the Turkic Uyghurs. Uyghur activists identify with the Tarim mummies, remains of an ancient people inhabiting 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 the research could affect their indigenous claim. Genetics research based on mtDNA and Y-DNA largely supports the Uyghur claim of indigenous descent. The Uyghurs are a mixed population, with predominantly East Eurasian maternal lineages and West Eurasian paternal lineages, and in this respect are similar to the Bronze Age mummies of the Tarim Basin. Origin of modern nomenclature The term "Uyghur" was not used to refer to a specific existing ethnicity in the 19th century: it referred to an 'ancient people'. A late-19th-century encyclopedia entitled The Cyclopædia of India and of Eastern and Southern Asia said "the Uigur are the most ancient of Turkish tribes and formerly inhabited a part of Chinese Tartary (Xinjiang), now occupied by a mixed population of Turk, Mongol and Kalmuck". Before 1921/1934, Western writers called the Turkic-speaking Muslims of the oases "Turki" and the Turkic Muslims who had migrated from the Tarim Basin to Ili, Ürümqi and Dzungaria in the northern portion of Xinjiang during the Qing dynasty were known as "Taranchi", meaning "farmer". The Russians and other foreigners referred to them as "Sart", "Turk" or "Turki". In the early 20th