Since Goshirakawa's own enthronement had occurred with the understanding that Morihito would succeed him to the throne, Shinzei dared not refuse Bifukumonin's request, and so in August, 1158, in what is known in the "Heihanki" as 'a Buddha's joint decision with another Buddha,' or in other words a negotiation between the two powerful figures, Shinzei and Bifukumonin, in which it was decided for Goshirakawa to abdicate in favor of Imperial Prince Morihito (who became Emperor Nijo).
もともと後白河の即位は守仁即位までの中継ぎとして実現したものであり、信西も美福門院の要求を拒むことはできず、保元3年（1158年）8月「仏と仏との評定」（『兵範記』）、すなわち信西と美福門院の協議により後白河天皇は守仁親王に譲位した（二条天皇）。