Shomyo is a kind of music that adds melodic patterns to the chanted words of shingon, that is, sacred Buddhist words in Sanskrit, or other Buddhist texts in all kinds of languages. It originated in India, the birthplace of Buddhism and then went to China. In China, the Buddhist scriptures were translated into Chinese and new texts were written as well and the forms of singing were arranged and adapted. In the 5th and 6th centuries, this was transmitted to Japan along with Buddhism and was called Shomyo. This oldest form of Shomyo played an important part in the ceremonies for the dedication of the great Buddha at Todaiji Temple in Nara in 752.
In the 9th century, Saichu and Ennin traveled to Tang Dynasty China and brought back new forms of esoteric and Pure Land Buddhism and new forms of Shomyo as well. Saichu founded the Enryakuji temple on Mt. Hiei, and established a new form of Shomyo called Tendai Shomyo, which included and elaborated on the earlier Shomyo. But it was Ennin who should really be considered the founder of Tendai Shomyo. In his ten years of study in Tang Dynasty China, he gained a profound knowledge of the rituals of Buddhism and established the foundations of Shomyo chanting.