Sun Yat-sen (12 November 1866 – 12 March 1925) was a Chinese revolutionary, first president and founding father of the Republic of China. As the foremost pioneer of Republic of China, Sun is referred to as the "Father of the Nation" in the Republic of China (ROC), and the "forerunner of democratic revolution" in the People's Republic of China. Sun played an instrumental role in the overthrow of the Qing dynasty during the years leading up to the Double Ten Revolution. He was appointed to serve as Provisional President of the Republic of China, when it was founded in 1912. He later co-founded the Kuomintang (KMT), serving as its first leader. Sun was a uniting figure in post-Imperial China, and remains unique among 20th-century Chinese politicians for being widely revered amongst the people from both sides of the Taiwan Strait.Although Sun is considered one of the greatest leaders of modern China, his political life was one of constant struggle and frequent exile. After the success of the revolution, he quickly resigned, due to Beiyang Clique pressure, from his post as President of the newly founded Republic of China, and led successive revolutionary governments as a challenge to the warlords who controlled much of the nation. Sun did not live to see his party consolidate its power over the country during the Northern Expedition. His party, which formed a fragile alliance with the Communists, split into two factions after his death. Sun's chief legacy resides in his developing of the political philosophy known as the Three Principles of the People: nationalism, democracy, and the people's livelihood.