He followed up this success by subjugating two powerful tribes: the Tanguts, who lived in the area
between the 'Aza and the Sumpa of Rgyaron (the vassal-state through which the Tibetans had probably entered the 'Aza lands), and the Po-lan, who were located in the area between the
'Aza and Central Tibet." It is notable that the Tibetans definitely did not attack the 'Aza from the west or the north (i.e., from Central Asia) or even from the southwest. The Tibetan state originated in the agricultural south, and, at the time of this war, its strength still lay largely in southerly and easterly lands.
