text: The Uyghurs in Turfan and Qomul founded Qocho and adopted Manichaeism and Buddhism as their religions, while those in Gansu first founded the Ganzhou Uyghur Kingdom and became subjects of the Western Xia; their descendants are the Yugurs of Gansu. The Western Yugur language is the descendant of Old Uyghur.
  The Kingdom of Qocho survived as a client state of the Mongol Empire but was conquered by the Muslim Chagatai Khanate, which conquered Turfan and Qomul and Islamized the region. Old Uyghur then became extinct in Turfan and Qomul.
  The Uyghur language that is the official language of the Xinjiang Uyghur Autonomous Region is not descended from Old Uyghur. It is a descendant of the Karluk languages spoken in the Kara-Khanid Khanate, in particular the Khākānī language described by Mahmud al-Kashgari. The only surviving descendant of Old Uyghur is Yellow Yughur, spoken in the Gansu region of China.
  Features
  Old Uyghur had an anticipating counting system and a copula dro, which is passed on to Western Yugur.
  Literature
  Much of Old Uyghur literature is religious texts regarding Manichaeism and Buddhism, with examples found among the Dunhuang manuscripts. Multilingual inscriptions including Old Uyghur can be found at the Cloud Platform at Juyong Pass and the Stele of Sulaiman.
  Script
  Qocho, the Uyghur kingdom created in 843, originally used the "runic" Old Turkic alphabet with a "anïγ" dialect. The Old Uyghur alphabet was adopted from local inhabitants, along with a "ayïγ" dialect, when they migrated into Turfan after 840.