The best-known figures are Abbé Fulbert Youlou (1917–72), a former Roman Catholic priest who served as president from 1960 to 1963, as well as mayor of Brazzaville; Alphonse Massamba-Debat (1921–77), president from 1963 to 1968; and Marien Ngouabi (1938–77), who came to power in a 1968 coup and was president from 1968 to 1977. Denis Sassou-Nguesso (b. 1941) became president in 1979. Prominent author and playwright Emmanuel Dongala-Boundzeki (b. 1941) is also a chemistry professor at Marien Ngouabi University in Brazzaville.