In 1854, the first year of Iesada's reign, Commodore Perry landed in Japan and forced an end to the isolation policy of the shogunate. However, the treaties signed between Japan and the western powers, particularly the Harris Treaty of 1858, put Japan at a serious disadvantage. In the same year, both Iesada and Nariakira died. Nariakira named his nephew, Shimazu Tadayoshi, as his successor. As Tadayoshi was still a child, his father, Shimazu Hisamitsu, effectively held the power in Satsuma.