元朝秘史
"The Secret History of the Mongols" begins thus: "There came into the world a "Borte Chono" (blue-gray wolf) whose destiny was Heaven's will. His wife was a "Gua Maral" (beautiful fallow doe). They traveled across the inland sea and when they were camped near the source of the Onon River in sight of Burkhan Khaldun, their first son was born, named Bat Tsagaan."