Ii Naosuke
Nobumasa was born at the domain's Edo residence, and was received in formal audience by Shōgun Tokugawa Ienari in 1835. He became daimyō in 1847 on the death of his father. In 1848, he was promoted to the post of "sōshaban" within the shogunal administration. In 1858, he rose to the post of "jisha-bugyō", and subsequently was appointed a "wakadoshiyori" under the "Tairō" Ii Naosuke. In 1860 he was appointed a "rōjū," and placed in charge of foreign affairs. Ii Naosuke was assassinated in the Sakuradamon Incident in 1860 and Andō Nobumasa became a leading councilor of state together with Kuze Hirochika. Among the many problems he faced in foreign affairs during this Bakumatsu period, was them the conclusion of a commercial treaty with Prussia, the assassination of Henry Heusken, and the appearance of a Russian warship claiming Tsushima Island for the Russian Empire.