A peninsula and former country of eastern Asia between the Yellow Sea and the Sea of Japan. Site of an ancient civilization dating to the 12th century BC, the peninsula was united as a kingdom in the 7th century AD and despite a Mongol invasion (13th century) remained unified until the Japanese occupation of 1910 to 1945. After World War II the Soviet- and US-occupied territories formed separate republics, and a North Korean invasion of the south led to the Korean War (1950-1953). The peninsula is now divided between North Korea and South Korea.