According to Clear Mirror on Royal Genealogy, Tongtsen was dispatched as envoys to Licchavi Kingdom (in modern Nepal) together with Thonmi Sambhota by the emperor Songtsen Gampo.

During this period, Tongtsen carried out a tax reform in 653, conducted a census in 654, and made the first law of Tibet in 655.

Tibet conquered glo po (Ngari) and rcang rgya (Tsang) in 652, and finally 'A-zha (which was called "Tuyunhun" by Chinese people) in 663.

Tongtsen left in 'A-zha to defend against Tang China, and was dismissed by Mangsong due to his age.

Not long after his successor Omade Lotsen was executed because the "guilty of rebellion", and the position turned back to him.