The primary cause of the Korean War (1950-1953) was the division of Korea into two separate states after World War II. Following Japan's defeat, Korea was split at the 38th parallel, with the North backed by the Soviet Union and the South supported by the United States. Tensions escalated as both governments sought to unify the peninsula under their ideologies: communism in the North and democracy in the South. The war began on June 25, 1950, when North Korean forces invaded South Korea in an attempt to achieve unification. The conflict drew in international powers, resulting in a bloody stalemate and lasting division of the Korean Peninsula.