Since Bogü Khan, the ruler of Uighur Khanate(744-840), converted to Manichaeism in 763 CE, he quickly established Manichaeism as the state religion. In 840, the Uighur Khanate broke down, and they began to move westward. Part of the Khanate moved to the present-day Xinjiang area, and established a regime centered on Qoco and Bes-baliq, hence known historically as the Qoco Uighur Kingdom or West Uighur Kingdom. The Uighur royal family continued to accept Manichaeism. In 840, before the Uighur immigrated to the west, Manichaeism had been disseminated in the area south of the Tianshan Mountain, and Qoco became the center of western Manichaeism. During the Qo c o Uighur Kingdom period, although most local people converted to Buddhism, the Uighur royal family still followed Manichaeism. The above mentioned events are rarely recorded in Chinese historical records, but the unearthed Uighur, Chinese and Persian documents in Turpan and Dunhuang as well as the Persian and Arabic documents and other historical records contain much information about this, which fills a void in Chinese historical records. From these documents we can see that, from the end of the eighth century till the middle of the eleventh century, Manichaeism in the Qoco Uighur Kingdom was quite popular.
