Born in 1918, Nelson Mandela joined the African National Congress (ANC) in 1943, as a law student.
He and other ANC leaders campaigned against apartheid. Initially he campaigned peacefully but in the 1960s the ANC began to advocate violence, and Mr Mandela was made the commander of its armed wing.
He was arrested for sabotage and sentenced to life imprisonment in 1964, serving most of his sentence on Robben Island.
It was forbidden to quote him or publish his photo, but he and other ANC leaders were able to smuggle out messages of guidance to the anti-apartheid movement.
He was released in 1990 as South Africa began to move away from strict racial segregation - a process completed by the first multi-racial elections in 1994.
Mr Mandela, who had been awarded the Nobel Prize in 1993 jointly with Mr de Klerk, was elected South Africa's first black president. He served a single term, stepping down in 1999.
After leaving office, he became South Africa's highest-profile ambassador, campaigning against HIV/Aids and helping to secure his country's right to host the 2010 football World Cup.
He was also involved in peace negotiations in the Democratic Republic of Congo, Burundi and other countries in Africa and elsewhere.
INFO COURTESY: BBC