In a complicated series of maneuvers and counter-maneuvers, Japan pushed back the Russian fleet at the Battle of Port Arthur in 1905. With the conclusion of the 1904–1905 Russo-Japanese War with the Treaty of Portsmouth, the way was open for Japan to take control of Korea. After the signing of the Protectorate Treaty in 1905, Korea became a protectorate of Japan. Prince Itō was the first Resident-General of Korea, although he was assassinated by Korean independence activist An Jung-geun in 1909 at the train station at Harbin. In 1910 the Japanese Empire finally annexed Korea.