After Japan's surrender to the Allied Powers, division at the 38th Parallel marked the beginning of Soviet and U.S. trusteeship over the North and South, respectively. On August 15, 1948 the Republic of Korea was established, with Syngman Rhee as the first president; on September 9, 1948, the Democratic People's Republic of Korea was established under Kim Il Sung.
On June 25, 1950, North Korean forces invaded South Korea (see Korean War). Led by the U.S., a 16-member coalition undertook the first collective action under U.N. Command (UNC). Oscillating battle lines inflicted a high number of civilian casualties and wrought immense destruction. With the People's Republic of China's entry on behalf of North Korea in 1951, stalemate settled in close to the original line of demarcation.
Armistice negotiations, initiated in July 1951, finally concluded on July 27, 1953 at Panmunjom, in the now Demilitarized Zone (DMZ). The resulting Armistice Agreement was signed by the North Korean army, Chinese People's Volunteers and the U.S.- led and ROK supported United Nations Command. A peace treaty has never been signed.
Domestically, South Korea achieved amazing economic growth, with per capita income rising to 13 times the level of North Korea. However, South Korea experienced political turmoil under years of autocratic leadership. Military coups and assassinations characterized the country's first decades. But a vocal civil society emerged that led to strong protests against authoritarian rule. Composed primarily of university students and labor unions, protests reached a climax after Major General Chun Doo Hwan's 1979 military coup and declaration of martial law. A confrontation in Kwangju in 1980 left at least 200 civilians dead but consolidated nationwide support for democracy, paving the road for the first democratic elections in 1987.