History of South Korea
On August 15, 1948, the Republic of Korea was formally established, with Rhee Syngman as the first president. With the establishment of Rhee's government, de jure sovereignty also passed into the new government. On September 9, 1948, a communist regime, the Democratic People's Republic of Korea (North Korea), was proclaimed under Kim Il-sung. However, on December 12, 1948, by its resolution 195 in the Third General Assembly, the United Nations recognized the Republic of Korea as the sole legal government of Korea.
History of Seoul
After World War II and Korea's liberation, the city took its present name of "Seoul". When the Republic of Korea (South Korea) was declared, the new state adopted the city as its capital. In 1949, Seoul administrative area expanded to Ui-dong to the north, and Guro-dong and Daerim-dong to the south, recombining some areas which were annexed from original Seoul to Goyang County in 1914.