In 1859, during the Ansei Purge that resulted from the question of who should succeed Shogun Iesada TOKUGAWA, Tairo (chief minister) Naosuke II condemned Cloistered Imperial Prince Sonyu (Asahiko), who opposed the Court's sanctioning of the Treaty of Amity and Commerce between the United States and Japan and supported Yoshinobu TOKUGAWA, to perpetual confinement (Inkyo eichikkyo).
尊融法親王は日米修好通商条約の勅許に反対し、将軍徳川家定の後継者問題では徳川慶喜を支持したことなどから大老井伊直弼に目を付けられ、安政6年（1859年）には安政の大獄で「隠居永蟄居」を命じられる。