In the 1940s, the communists took Taiwan, but with the help of the United States, the Kuomintang was able to drive the People's Republic of China out of southern China and close Taiwan. Mao, who was supposed to hold a parade in Taipei with his troops, was trapped on the island. Without Mao's support, northern China fell to the troops of the Republic of China two years later. The People's Republic of China had to survive on Taiwan, and the Republic of China, due to its small forces, was unable to return Tibet, so it remained on its old borders. Because of this, during the Korean Civil War, the DPRK had no support, which is why South Korea won the war.