The Borjigin Mongols had emerged in central Mongolia as the leading clan of a loose federation after the migration of the Jurchen.

The principal Borjigin Mongol leader, Kabul Khan, begins a series of raids into Jin in 1135.

In 1162 (some historians say 1167), Temujin, the first son of Mongol chieftain Yesugei, and grandson of Kabul, is born.

Yesugei, who is chief of the Kiyat subclan of the Borjigin Mongols, is killed by neighboring Tatars in 1175, when Temujin is only twelve years old.

The Kiyat reject the boy as their leader and choose one of his kin instead.

Temujin and his immediate family are abandoned and apparently left to die in a semidesert, mountainous region.