The oldest Turkic religious statement is carved in stone. The Orkhon inscriptions of the early eighth century, raised in Mongolia for the rulers of the Second Turkic Khaganate, open with the blue sky above and the brown earth below and the sons of men between them, and they attribute the ruler's power to Tengri, heaven, and to a female earth and water power. Peter Golden's history sets those texts within the wider record of the steppe.
Around that framework sat the ordinary apparatus of steppe religion: spirits of place and of ancestors, sacred mountains, offerings of horses, and specialists who dealt with the spirits. The Tungusic word taken into Russian and from there into every European language as shaman came from this world, and it has since been applied to religious specialists on every continent, a generalisation the atlas treats with caution because it flattens what the word originally named.
Turkic peoples then adopted, at different times, most of the religions of Eurasia. The Uyghur khaganate took Manichaeism as a state religion in the eighth century, others took Buddhism, Christianity of the Church of the East spread widely among them, and the Khazar elite adopted Judaism, an episode whose extent is still argued over.