score:5
From the Wiki you linked:
Tengriism also played a large part in the religious denomination of the Gok-Turk Empire and the Great Mongol Empire. The name “Gok-Turk” translates as “Celestial Turk” which directly points out to the devotion to Tengriism. In the 13th century, Genghis Khan and several generations of his followers were also Tengrian believers until his fifth generation descendent Uzbeg Khan turned to Islam in the 14th century.