The Jurchen people had traditionally lived in Manchuria and were then divided into three tribes, the most powerful of which during the Ming dynasty was called Jianzhou Jurchens, living around the Changbai Mountains. In order to attack and suppress the Northern Yuan dynasty, the Hongwu Emperor sent military commissions to gain control of the Jurchen tribes in Manchuria. The Ming government divided the Jianzhou Jurchens into three wei (a military subdivision during the Ming dynasty), collectively known as the Three Wei of Jianzhou. The leaders of the Jurchen tribes were usually chosen as commanders of the wei.