In order to protect the northern border areas, the Ming dynasty decided to "pacify" the Jurchens in order to deal with its problems with Yuan remnants along its northern border. The Ming solidified control over Manchuria under the Yongle Emperor (r. 1402–1424), establishing the Nurgan Regional Military Commission of 1409-1435. Starting in the 1580s, a Jianzhou Jurchen chieftain, Nurhaci (1558–1626), started to unify Jurchen tribes of the region.