Minister Thonmi Sambhota, sent by King Songtsen Gampo to study in India, returned as the sole survivor of sixteen students. Drawing from the Gupta Brahmi script used for Sanskrit, he devised the Tibetan writing system during a retreat at Kukarmaru Palace in Lhasa. The script enabled translation of Buddhist texts into Tibetan and unified administrative communication across the expanding empire. Songtsen Gampo reportedly spent four years mastering the new script and grammar.