Pacification commissioners (xuanweishi 宣慰使) were originally high military officials supervising the peace in border regions. Their bureau was called xuanweishi si 宣慰使司. The title was first used during the Tang period 唐 (618-907) in 819, when Yang Yuling 楊于陵 was ordered to inspect the military situation of twelve prefectures, but was thereafter rarely applied (unlike the titles anfushi 安撫使 and xuanfushi 宣撫使). During the Yuan period 元 (1279-1368) pacification commissioners obtained also civilian jurisdiction in individual circuits, and belonged thus to the regular local administration. Commissioners in the border regions of the southwest were called aboriginal military commanders (duyuanshuai 都元帥). The Ming 明 (1368-1644) and Qing 清 (1644-1911) dynasties used the designation (rank 3B) for hereditary native chieftains (tusi 土司) in the southwest. They were given the title to express their function in the indirect rule (jimi 羈縻) over the aboriginal regions.