Nelson Mandela was imprisoned for 27 years, 18 of which were spent at the infamously cruel Robben Island Prison in South Africa, where he was held from 1964 - 1982. Mandela was released from imprisonment in 1990 despite having initially been handed a life sentence. At the time of his imprisonment, South Africa was ruled by the white supremacist system of apartheid, in which native black Africans were officially considered inferior in every way to colonial European citizens, also known as Afrikaners. Mandela was an anti-apartheid revolutionary who eventually became the first president of South Africa, and he was initially imprisoned on charges of incitement before being charged with conspiracy to overthrow the state in what is known as the Rivonia Trial.
Prisoner treatment at Robben Island Prison, which was a segregated facility intended only for black prisoners, was notoriously bad. Mandela was allowed only one visitor per year, could only write and receive a single letter every 6 months and was subjected to hard labor such as breaking rocks. However, despite these harsh conditions, Mandela's leadership instincts allowed him to gain some authority amongst the prison's staff and inmates. The skills he developed during his imprisonment are said to have helped shape his diplomatic talents.