For five centuries Korea was governed as an independent kingdom, a period that came to an end in 1910 with the annexation of Korea by Japan. Korea endured 35 years of harsh Japanese occupation that repressed Korean language and culture, exploited Korean labor and violently suppressed Korean nationalist movements.

After Allied victory in Europe in World War II and following the U.S. bombing of Hiroshima in August 1945, the Soviet Union abrogated a neutrality agreement with Japan and declared war, invaded Manchuria and drove south into the Korean peninsula to eliminate Japanese wartime resistance and secure important Pacific ports.

Alarmed at the swift movement of Soviet troops, American officers were ordered to define an American occupation zone and divided the country at the 38th parallel, placing the capital city of Seoul under American jurisdiction, while the USSR held de facto jurisdiction north of the 38th parallel. The division was incorporated into terms of general surrender of Japan and approved on August, 17 1945. Japan’s imperial rule thus came to an abrupt end, leaving a vacuum of governing authority.

In December 1945 the Moscow Conference placed Korea in a trusteeship for up to five years in preparation for a return to independence, but increasing Cold War hostilities deepened divisions, and by May 1946 movement across the 38th parallel required a permit.

A UN resolution in November 1947 called for free elections, removal of foreign troops, and establishment of a UN commission for Korea. The Soviet Union rejected the terms of UN resolution and thus UN-supervised elections were held in the south only on May 10, 1948. On August 15, the Republic of Korea formally took power from the U.S. military, with U.S. educated Syngman Rhee elected as the first president. In the North, the Democratic People’s Republic of Korea was declared on September 9, with North Korean communist leader Kim Il-sung designated as prime minister.

The division of Korea into separate governments was seen as controversial and temporary, with each side claiming to represent the legitimate government. Following repeated outbreaks of armed conflict along the border, tensions escalated dramatically on June 25, 1950, when North Korean forces invaded South Korea in an attempt to unify Korea by force, triggering the Korean War. Backed by Soviet military, the North overran much of the South until a U.S.-led, UN-authorized military response drove the North Korean invaders back. The UN forces then occupied most of the North, until Chinese forces crossed the border and pushed the UN forces back across the 38th parallel.

The Korean Armistice Agreement signed on July 27, 1953 effectively ended the Korean War, restoring the prewar boundaries and political status quo. The armistice was not peace treaty but a cease-fire between military forces. The armistice left North and South technically in a state of war, and as global Cold War tensions heightened during the 1950s and ‘60s, the Korean peninsula became a flashpoint, with conflicting geopolitical allegiances, economic models, and systems of government widening the gap between a once-unified people.