The history of the Republic of China begins after the Qing dynasty in 1912, when the Xinhai Revolution and the formation of the Republic of China put an end to 2,000 years of imperial rule. The Republic experienced many trials and tribulations after its founding which included being dominated by elements as disparate as warlord generals and foreign powers.
In 1928, the Republic was nominally unified under the Kuomintang (KMT; also called "Chinese Nationalist Party") after the Northern Expedition, and was in the early stages of industrialization and modernization when it was caught in the conflicts involving the Kuomintang government, the Chinese Communist Party (CCP), local warlords, and the Empire of Japan. Most nation-building efforts were stopped during the full-scale Second Sino-Japanese War against Japan from 1937 to 1945, and later the widening gap between the Kuomintang and the Communist Party made a coalition government impossible, causing the resumption of the Chinese Civil War, in 1946, shortly after the Japanese surrender to the Allied Powers in September 1945.
A series of political, economic and military missteps led to the KMT's defeat and its retreat to Taiwan (formerly "Formosa") in 1949, where it established an authoritarian one-party state under Generalissimo/President Chiang Kai-shek. This state considers and until the 1990s actively asserted itself to be the continuing sole legitimate ruler of all of China, referring to the communist government or "regime" as illegitimate, a so-called "People's Republic of China" (PRC) declared in Beijing (Peking) by Mao Zedong in 1949, as "mainland China" and "communist bandit". The Republic of China was supported for many years — even decades — by many nations, especially the United States who established a 1954 Mutual Defense treaty. After political liberalization began in the late 1960s, the PRC was able — after a constant yearly campaign in the United Nations — to finally get approval in 1971 to take the seat for "China" in the General Assembly, and more importantly, be seated as one of the five permanent members of the Security Council.