Sun Yat-sen (12 November 1866 - 12 March 1925) and known as Sun Zhongshan on the mainland, was a Chinese statesman, physician, and political philosopher, who served as the first provisional president of the RoC and the first leader of the KMT. He is called the "Father of the Nation" in the RoC, and the "Forerunner of the Revolution" in the PRC for his instrumental role in the overthrow of the Qing dynasty during the Xinhai Revolution.

Sun Yat-sen was a Cantonese doctor of Western medicine who studied in Hong Kong and worked in Macao. He became actively involved in politics in 1894 when he founded the Revive China Society. After an attempted uprising in Guangzhou in 1895 failed he went into exile abroad where he continued to develop his political philosophy and attempted to rally support for an anti-Manchu rebellion. He returned to China in 1911 and was elected president of the provisional government after the overthrow the Qing dynasty. He resigned from that position in 1912 after facing opposition from more conservative reformers and, after an unsuccessful revolt in 1913, left the country once more. With assistance from the Soviet Union, he finally regained power in 1923 and was elected President of the Republic. He founded the KMT, the most important political party after 1911, and espoused the Three Principles of the People (Sanminzhuyi), that is nationalism, democracy and the people's livelihood.

His part in the Founding of the Republic was pivotal but Building the Republic was anything but straightforward