Tibetan Buddhism, developed in the 7th to 9th centuries when the Tibetan shamanistic Bon religion was assimilated to Mahayana Buddhism from India. Lamaism was persecuted in the 9th century by King gLang Dar Mar but recovered in the 11th century when the monasteries became powerful landowners. It was reformed by Tsong-kha-pa (1357–1419), founder of the de-lugs-pa sect (or Yellow Hats) – precursors of the line of Dalai Lamas who have been the temporal and spiritual leaders of Tibet since the 17th century.