The Republic of China (ROC), commonly known simply as China, was a sovereign state based on mainland China from 1912 to 1949 prior to the Government of the Republic of China's relocation to Taiwan, where it continues to be based today. The ROC was established on 1 January 1912 during the Xinhai Revolution against the Qing dynasty. On 7 December 1949, the ROC's government ruled by the Kuomintang (KMT; Chinese Nationalist Party) was moved from Nanjing to Taipei following the KMT's de facto defeat by the Chinese Communist Party (CCP) in the Chinese Civil War. The CCP-led People's Republic of China (PRC) was established in mainland China upon its official proclamation on 1 October 1949, while the ROC retains actual control over the Taiwan Area ("Free Area") with the political status of Taiwan remaining in dispute to this day. The ROC was formally declared on 1 January 1912, before the Xuantong Emperor of the Qing dynasty abdicated on 12 February 1912. Sun Yat-sen, the ROC's founder and provisional president, served only briefly before handing over the presidency to Yuan Shikai, the leader of the Beiyang Army. Yuan quickly became authoritarian and used his military power to control the administration, which consequently became known as the "Beiyang government". Yuan even attempted to replace the Republic with his own imperial dynasty until popular unrest forced him to back down. When Yuan died in 1916, the country fragmented between the various local commanders of the Beiyang Army. This began the Warlord Era of decentralized conflicts between rival warlord cliques. The most powerful of these cliques, notably the Zhili and Fengtian cliques, at times used their control of Beijing to assert claims to govern the entire Republic. Meanwhile, the nationalist KMT under Sun's leadership attempted multiple times to establish a rival national government in Guangzhou. Sun was finally able to take Canton with the help of weapons, funding, and advisors from the Soviet Union. As a condition of Soviet support, the KMT formed the "First United Front" with the CCP. CCP members joined the KMT and the two parties cooperated to build a revolutionary base in Canton. Sun planned to use this base to launch a military campaign northwards and reunify the rest of China. Sun's death in 1925 precipitated a power struggle that eventually resulted in the rise of General Chiang Kai-shek to KMT chairmanship. Thanks to strategic alliances with warlords and help from Soviet military advisors, Chiang was able to lead a successful "Northern Expedition". By 1927, Chiang felt secure enough to end the alliance with the Soviet Union and purged the Communists from the KMT. In 1928, the last major independent warlord pledged allegiance to the KMT's Nationalist government in Nanjing. While there was relative prosperity during the following ten years under Chiang Kai-shek, the ROC continued to be destabilized by the Chinese Civil War, revolts by the KMT's warlord allies, and steady territorial encroachments by Japan. Although heavily damaged by the purge, the CCP gradually rebuilt its strength by focusing on organizing peasants in the countryside. Warlords who resented Chiang's attempts to take away their autonomy and incorporate their military units into the National Revolutionary Army repeatedly led devastating uprisings, most significantly the Central Plains War. In 1931, the Japanese invaded Manchuria. They continued a series of smaller territorial encroachments until 1937, when they launched a full-scale invasion of China. World War II devastated China, leading to enormous loss of life and material destruction. The war between China and Japan continued until the surrender of Japan at the end of World War II in 1945, which led to Taiwan being placed under Chinese administration. In the aftermath of World War II, civil war resumed between the areas liberated by the KMT and those liberated by the CCP. The CCP's People's Liberation Army managed to defeat the larger and better-armed National Revolutionary Army due to better military tactics and corruption of the ROC leadership. In 1949, the ROC repeatedly moved its capital to avoid the Communist advance—first to Guangzhou, followed by Chongqing, Chengdu, and lastly, Taipei. In October 1949, the CCP established the PRC. Remnants of the ROC government would hang on in mainland China until late 1951. The ROC was a founding member of the League of Nations and later the United Nations (including its Security Council seat) where it maintained until 1971, when the PRC took over its membership. It was also a member of the Universal Postal Union and the International Olympic Committee. With a population of 541 million in 1949, it was the world's most populous country. Covering 11.4 million square kilometres (4.4 million square miles) of claimed territory, it de jure consisted of 35 provinces, 1 special administrative region, 2 regions, 12 special municipalities, 14 leagues, and 4 special banners. Source: Wikipedia (en)