Nelson Mandela was professionally involved in politics.
The African National Congress ( ANC ) is the Republic of South Africa 's governing social democratic political party . Nelson Rolihlahla Mandela ( [ mænˈdɛlə ] 18 July 1918 -- 5 December 2013 ) was a South African anti-apartheid revolutionary , politician , and philanthropist , who served as President of South Africa from 1994 to 1999 . Ideologically an African nationalist and socialist , he served as President of the African National Congress ( ANC ) party from 1991 to 1997 . Mandela was appointed President of the ANC 's Transvaal branch , rising to prominence for his involvement in the 1952 Defiance Campaign and the 1955 Congress of the People . Internationally , he acted as mediator in the Pan Am Flight 103 bombing trial and served as Secretary-General of the Non-Aligned Movement from 1998 to 1999 .