Tendai (天台宗, Tendai-shū), also known as the Tendai Dharma Flower School (天台法華宗, Tendai hokke shū, sometimes just Hokkeshū), is a Mahāyāna Buddhist tradition with significant esoteric elements that was officially established in Japan in 806 by the Japanese monk Saichō. The Tendai school, which has been based on Mount Hiei since its inception, rose to prominence during the Heian period (794–1185). It gradually eclipsed the powerful Hossō school and competed with the rival Shingon school to become the most influential sect at the Imperial court.
By the Kamakura period (1185–1333), Tendai had become one of the dominant forms of Japanese Buddhism, with numerous temples and vast landholdings. During the Kamakura period, various monks left Tendai to found new Buddhist schools such as Jōdo-shū, Jōdo Shinshū, Nichiren-shū and Sōtō Zen. The destruction of the head temple of Enryaku-ji by Oda Nobunaga in 1571, as well as the geographic shift of the capital away from Kyoto to Edo, ended Tendai's dominance, though it remained influential.