After joining the African National Congress (ANC) in 1944 and taking part in resistance against the largely white, ethnic-Afrikaner National Party's apartheid policies, Nelson Mandela eventually went on trial in what became known as the marathon Treason Trial of 1956-1961 (in which all defendants would eventually be acquitted). With the ANC banned, in 1961 he co-founded its military wing, Umkhonto we Sizwe (Spear of the Nation) but was arrested in 1962 and sentenced to five years' imprisonment with hard labor. In 1964 the sentence was furthered to life imprisonment for his allegedly plotting to violently overthrow the government. Until 1982, Mandela was kept at the infamous Robben Island prison, off Cape Town, before moving to Pollsmoor prison on the mainland.
Despite his incarceration, his reputation grew, along with the antiapartheid movement itself. Upon his release in 1990, Mandela threw himself into his life's work and became leader of the ANC. By 1994, South Africa's first multiracial elections saw the ANC win 62% of the vote. Mandela duly became the country's first black President, with the National Party's F. W. de Klerk as his first deputy and Thabo Mbeki as the second in the Government of National Unity.