From the early Heian period, the Retired Emperor started to be called by ingo (a title of the Retired Emperor), and the Retired Emperor's immediate authorities, Toneri (palace servant) and Zoshiki (low-level functionary) were assigned to handle land management and routine tasks of the Retired Emperor called "In."
平安時代前期ごろから、上皇を院号で呼称することが見られるようになったが、院と呼ばれた上皇の所務・雑務を取り仕切るために、上皇直属の官庁・舎人・雑色などがあてがわれていた。