Nelson Mandela was imprisoned for 27 years because he was found guilty of conspiracy and sabotage to overthrow the government of South Africa, together with other eight National African Congress Leaders. He was sentenced to life imprisonment in 1964 and was released in 1990 after serving for 27 years in jail.
Nelson Mandela and the other eight prisoners passed through a hard life in prison whereby they were given little food and were completely isolated. They were also assigned a strenuous job of pounding rocks into gravel. However, while in prison, Nelson Mandela and his colleagues formed a group that helped them to remain focused and survive in such harsh and oppressive circumstances.
In 1982, Nelson Mandela was transferred to the maximum security Pollsmoor prison, which is where it is believed that he contracted tuberculosis. After being diagnosed with tuberculosis, Mandela suffered respiratory ailments until his death. At the age of 71, and after serving a jail term of 27 years, he was released in 1990 with the help of an international movement.
During the reign of the South African president F.W. de Klerk, Mandela helped in negotiating the end of the apartheid. In 1993, he won the Nobel Peace Prize, and in 1994, his party won the multi-racial democratic elections. Mandela became the president of South Africa, but only served for one term from 1994 to 1999.