I was a South African. I worked to put an end to apartheid (racial segregation) in South Africa. Initially, I did this in a non-violent manner, but later I declared war on the Government, and so I was sentenced to life imprisonment in 1964. However, in 1990 President Frederik Willem de Klerk released me, after which I won the first multiracial elections in South Africa and became the President again. Who am I?

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Question 1.