Western Turkic Khaganate
Tengrism was the religion of several medieval states, such as the Göktürk Khaganate, Western Turkic Khaganate, Old Great Bulgaria, Danube Bulgaria, Volga Bulgaria, and Eastern Tourkia (Khazaria) Turkic beliefs contains the sacral book "Irk Bitig" from Uyghur Khaganate.