After Naosuke II was assassinated in the 1860 Sakuaradamon-gai no hen (incident outside Sakurada-mon Gate), he recommended kobu gattai (integration of the court and the shogunate) and marrying Kazunomiya off to someone outside the Imperial family.
安政7年（1860年）に桜田門外の変で井伊直弼が暗殺された後、公武合体をすすめ和宮降嫁を推進した。