The Korean Empire (Korean: 대한제국; Hanja: 大韓帝國; Daehan Jeguk; literally the "Great Korean Empire") was established on October 1897 after Joseon (or the Yi Dynasty) ended its status tributary state of the Manchu Qing Empire. One of its Emperors, Gojong, oversaw Korea's partial modernisation under Russian influence. Japan eventually wary of Korea's increasingly successful modernisation attempt. This resulted in its subjugation as the protectorate of Japan in 1905, after Japanese victory in the Russo-Japanese war. After the assassination of governor-general Itō Hirobumi, Korea became a directly-controlled colony through the Japan--Korea Treaty of 1910.
After a massive purge in anti-Japanese politicians, Korea achieved independence on the middle of 1911, and continued its modernisation attempt, though this time it is heavily dependent on Japan, its largest consumer market. In 1917, after growing nationalist sentiment, Korea's government installed its then-exiled "House of Yi", led by the Emperor Yi Un, as its royal family and Korea officially changed into an unitary parliamentary constitutional monarchy with real political power being held by the National Diet and the Premier.