Thonmi Sambhota

Thonmi Sambhota (Thönmi Sambhoṭa, aka Tonmi Sambhodha;, Tib. ཐོན་མི་སམྦྷོ་ཊ་, Wyl. thon mi sam+b+ho Ta; b. seventh cent.) is traditionally regarded as the inventor of the Tibetan script and author of the "Sum cu pa" and "Rtags kyi 'jug pa" in the 7th century AD. Thonmi Sambhota is not mentioned in any of the "Old Tibetan Annals" or other ancient texts, although the "Annals" does mention writing shortly after 650. The two treaties attributed to him must postdate the 13th century.
Of the students sent to India, Thonmi Sambhota, said to have been the fourth of seven wise ministers of the emperor Songtsen Gampo, was the only one to return to Tibet. It seems that the Tibetan script he devised, in what is believed to be Pabonka Hermitage was based on the Brahmi and Gupta scripts which had been in use in India since c. 350 CE.
King Songtsen Gampo is said to have retired for four years to master the new script and grammar and then made many translations including twenty Avalokitesvara texts. Other translators quickly added to the corpus of Buddhist translations. The "Six Codices of the Tibetan constitution" were drawn up and court records, genealogies, legends and poetry were preserved in writing.