Uyghur state (744–840)

The Uyghurs, who were subjects to the Göktürks, revolted in 745 and founded the Uyghur Khaganate which replaced the Eastern Turkic Khaganate. The Uyghur kagan Bayanchur established Ordu-Baliq City on the Orkhon river in 751. The Tang Empire invited the Uyghurs to subdue the An Lushan rebellion in 755. Successful campaigns of the Uyghur Khaganate led to a peace with the Tang dynasty of China which paid compensation for the suppression of An in silk and grain for 12 years after 766.^[23] Though a faction of the Uyghurs were Buddhists, the Manichaeism became the official religion of the Khaganate in the 8th century. Nevertheless, the majority of the Uyghurs remained shamanists. The culture and economy of the Uyghur Kaganate were more advanced than those of its predecessors. The Uyghurs used a 12-month calendar and calculated the dates of solar and lunar eclipses. The Uyghurs developed their own writing system based on the Sogdian script. The Tang dynasty surreptitiously encouraged the Yenisei Kirghiz and the Karluks to attack the Uyghurs and the Uyghur Khaganate fell under an invasion of the Yenisei Kirghiz in 840.

The destruction of Uyghur Khaganate by Yenisei Kirghizes resulted in the end of Turkic dominance in Mongolia. According to historians, Kirghiz were not interested in assimilating newly acquired lands. The Kirghiz state was centered on Khakassia.