In the late 11th century, Emperor Gosanjyo appointed the priest Syosin 性信 (the first Omuro of Ninnaji) as an imperial priest (Gojiso). Successive retired Emperors appointed their sons as the Omuro of Ninnaji. Although this position was outside of the official ranking system of priests (Sogosei), the Omuro became the highest ranking priest in the Singon hierarchy. The Omuro, a chief of Ninnaji-temple, also administered Singon rites and intervened in other temple affairs. The Omuro performed " the Kujyakukyo-ho 孔雀経法 ritual", the most important Singon ritual. By mid 12th century, the Omuro monopolized all major Singon esoteric rituals. Syukaku 守覚, the 5th Omuro, reorganized the ritual for the royal family (Koke-Misiho 公家御修法) of Singon and Tendai sect in the late 12th century, in order to prevent temples from cursing the retired Emperor during the Genpei war (1180-5). Singon temples managed by the Omuro prayed for the retired Emperor and cursed temples which demonstrated (Goso) against him. The Omuro of Ninnaji constituted an extension of the authority of retired Emperors through esoteric Buddhism. As the power of retired Emperors waned, so too did the Omuro.
