On April 14, 1879, his family asked permission of the Imperial Household Ministry to confine Tomotane at home because of his mental disease, and on the following day, they were granted.
明治12年（1879年）4月14日、親族らは精神的な病気を理由に宮内省に誠胤の自宅監禁を願い、翌日、許可される。