Ennin (Jikaku Daishi, 794-864) and Enchin (Chisho Daishi, 814-891) both studied in Tang China, brought back lots of Buddhist scriptures, and worked to develop Mt. Hiei's esoteric teachings.
円仁（慈覚大師、794-864）と円珍（智証大師、814-891）はどちらも唐に留学して多くの仏典を持ち帰り、比叡山の密教の発展に尽くした。