Tadayasu played an active role during the period from the end of the Edo period to the Meiji Restoration and he was opposed to joyaku chokkyo (literally, the imperial approval of the treaty) and promoted koka (the marriage of an Imperial Princess to a subject) of Imperial Princess Kazunomiya Chikako.
幕末から、明治維新にかけて活躍し、条約勅許に反対、和宮親子内親王の降嫁を推進した。