[4] Historically known as Powo or Poyul, it was the seat of a quasi-independent kingdom until the early 20th century when troops of the Dalai Lama's Lhasa government integrated it into the central Tibetan realm.

[4] Po-to or Upper Powo consists of the basin of another river Poto Tsangpo, which originates within the Pome County, along with its tributary Yarlung Chu.

Its inhabitants had a reputation as fearsome savages which meant most travellers kept clear of it and so it was one of the least known areas in the Tibetan traditional feudal establishment.

Its power extended south over the Doshong La pass, to include the location of one of these earthly paradises called "Padma bkod" (written variously Pema köd, Pemakö and Pemako), literally 'Lotus Array', a region in the North-Eastern Province of Upper Siang of Arunachal Pradesh.

By 1931 the Lhasa government had expelled the last Ka gnam sde pa ('king') and established two garrisons.