In 1949, Kim Il Sung – the leader of north Korea, approached Stalin and Mao Zedong (the leader of China, which had turned Communist in 1949), and persuaded them to allow him to attack South Korea. When Syngman Rhee (the leader of South Korea) boasted that he would attack North Korea, the North Koreans attacked (25 June 1950). They easily defeated the South Korean army and by September 1950 had conquered all South Korea apart from a small area around Pusan in the south.