History of Korea
After the end of WWII in 1945, the Allies divided the country into a northern area (protected by the Soviets) and a southern area protected (primarily by the United States). In 1948, when the powers failed to agree on the formation of a single government, this partition became the modern states of North and South Korea. The peninsula was divided at the 38th Parallel: the "Republic of Korea" was created in the south, with the backing of the US and Western Europe, and the "Democratic People's Republic of Korea" in the north, with the backing of the Soviets and the communist People's Republic of China. The new premier of North Korea, Kim il-Sung, launched the Korean War in 1950 in an attempt to reunify the country under Communist rule. After immense material and human destruction, the conflict ended with a cease-fire in 1953. The two nations officially remain at war because a peace treaty was never signed. In 1991, both states were accepted into the United Nations.
History of South Korea
Korea was administratively partitioned in 1945, at the end of World War II. As Korea was under Japanese rule during World War II, Korea was officially a belligerent against the Allies by virtue of being Japanese territory. The unconditional surrender of Japan led to the division of Korea into two occupation zones (similar to the four zones in Germany), with the United States administering the southern half of the peninsula and the Soviet Union administering the area north of the 38th parallel. This division was meant to be temporary (as was in Germany) and was first intended to return a unified Korea back to its people after the United States, United Kingdom, Soviet Union, and Republic of China could arrange a single government for the peninsula.