Zhangzhung or Shangshung was an ancient kingdom in western and northwestern Tibet, existing from about 500 BCE to 625 CE, pre-dating Tibetan Buddhism.
The outer is what we might call Western Tibet, from Gilgit in the west to Dangs-ra khyung-rdzong in the east, next to lake gNam-mtsho, and from Khotan in the north to Chu-mig brgyad-cu rtsa-gnyis in the south.
"[5]Archeological work on the Chang Tang plateau in 2010 found possible evidence of an Iron Age culture in the area which some have tentatively identified as that of the Zhangzhung.
[7] The records of the Tang Annals do, however, seem to clearly place these events in the reign of Songtsen Gampo for they say that in 634, Yangtong (Zhangzhung) and various Qiang tribes, "altogether submitted to him".
[13] Zhangzhung revolted soon after the death of King Mangsong Mangtsen or Trimang Löntsän (Wylie: Khri-mang-slon-rtsan, r. 650–677), the son of Songtsen Gampo, but was brought back under Tibetan control by the "firm governance of the great leaders of the Mgar clan".
A modern Kinnauri language called by the same name (pronounced locally Jangshung) is spoken by 2,000 people in the Sutlej Valley of Himachal Pradesh who claim to be descendants of the Zhangzhung.
Bonpos claim that Tonpa Shenrab Miwoche lived some 18,000 years ago, and visited Tibet from the land of Tagzig Olmo Lung Ring, or Shambhala.
[17] Bonpos also suggest that during this time Lord Shenrab Miwoche's teaching permeated the entire subcontinent and was in part responsible for the development of the Vedic religion.