Sun Yat-sen (12 November 1866 – 12 March 1925) is a Chinese revolutionary, first president and founding father of the Republic of China ("Nationalist 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 plays an instrumental role in the overthrow of the Qing dynasty during the Double Ten Revolution.

Although he is in St. Louis, Missouri at the time, he is appointed to serve as president of the Provisional Republic of China, when it is founded in 1912.

He later co-founds the Kuomintang (KMT), serving as its first leader.

Sun is 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 is one of constant struggle and frequent exile.

After the success of the revolution, he quickly falls out of power in the newly founded Republic of China, and leads successive revolutionary governments as a challenge to the warlords who control much of the nation.

Sun does not live to see his party consolidate its power over the country during the Northern Expedition.

His party, which forms a fragile alliance with the Communists, splits 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.