Tängri is the god of the eternal blue heaven, the highest power of the pre-Islamic Turkic and Uyghur world. The word names at once the visible firmament and the deity who dwells in and rules it. In the Orkhon and Tonyukuk inscriptions Tängri creates the khagan, grants the heaven-sent fortune (qut) by which rulers govern, and, invoked beside Umay and the sacred Earth-Water, delivers victory to the Turks. Kāshgarī records that the unbelieving Turks called the sky teŋri and applied the same word to anything they held great or exalted. Though the Uyghur court adopted Manichaeism in the 760s and later Islam, the heaven-cult persisted as a substratum in oath, blessing and folk belief.