元史
According to Subutai's biography in the History of Yuan, Subutai's father was once driving a herd of sheep in order to present them to his overlord, Taizu (Genghis Khan). Encountering robbers, he was seized. Huluhun (Subutai's brother) and Subutai arrived in good time, and with their lances stabbed some of the robbers. Horses and men fell together, and the remainder of the band withdrew and departed. Consequently, they relieved their father's difficulty, and the sheep were able to attain the emperor's station.