Walter Sisulu
He was one of many people, including Nelson Mandela to be found guilty of treason during trials between 1956 and 1961. He was sent to prison for 6 years because of this. While free on bail, he went into hiding. He was found in 1963 and put on trial again. In 1964, he as sent to prison for the rest of his life. He was released from prison in 1989.