Until the Heian period, the Shinno who became a priest was called Nudo Shinno, Hoshi Shinno, and Zenji Shinno, but since the Prince of Emperor Shirakawa was given an order to become Shinno by the emperor after becoming a priest and came to be called Kakugyo Hosshinno, the title took hold as a title for imperial family members who became Shinno after becoming a priest.
平安時代まで出家した親王は、入道親王、法師親王、禅師親王と呼称していたが、白河天皇の皇子が　出家後に親王宣下を受けたことで、覚行法親王と呼ばれて以来、出家後に親王になった皇族の称として定着した。