Deng Xiaoping (August 22, 1904 — February 19, 1997, formerly known as Deng Xiansheng, was a Chinese Marxist-Leninist revolutionary and theorist, who was the de facto head of state of the People's Republic of China from 1977 to 1992, following the death of Mao Zedong in 1976. He was born in Guang'an, Sichuan. His primary contributions to Marxist theory include the Socialist Market Economy, Reform and Opening Up, the Four Modernizations and the Four Cardinal Principles, which are included under his theoretical thinking which is known as Deng Xiaoping Theory.