Answer:
After the Japanese surrendered at the end of World War II, Korea fell under the control of the United States and the Soviet Union.
Explanation:
From 1910 to 1945, the Korean peninsula was occupied by Japan, who subjected it economically, socially, and politically, reducing it to a merely colonial status.
With the Japanese surrender in World War II, the Korean peninsula began to be administered by the United States, in the south, and the Soviet Union, in the north. Each power in turn installed a Korean government that claimed to be sovereign over the entire peninsula: in 1948 South and North Korea were legally established as sovereign nations, each claiming the entire territory of the peninsula.
In 1950, North Korea invaded South Korea, trying to reunify the Korean territory under a communist regime. This action triggered the Korean War, which lasted from 1950 to 1953, and which saw the participation of South Korea supported by an American-led UN coalition against North Korea, supported by China and the Soviet Union.
The war ended in a status quo ante bellum, that is, the previous situation of division of the peninsula was not modified. As of today, that is still the current situation, with two different republics in each sector of the Korean peninsula.