Nelson Mandela celebrates the 20th anniversary of his release from prison on Thursday.

Here are key dates in his life.

July 18, 1918 - Born Nelson Rolihlahla Mandela near Qunu, in Transkei (now Eastern Cape), the youngest son of a counsellor to the chief of his Thembu clan.

1944 - Founds African National Congress (ANC) Youth League with Oliver Tambo and Walter Sisulu.

-- Marries his first wife Evelyn, with whom he had a daughter and two sons. They were divorced in 1957.

1952 - Mandela and others arrested and charged under Suppression of Communism Act; given suspended prison sentence.

-- Elected deputy national president of ANC

1958 - Marries Winnie Madikizela. They separated in April 1992 and were divorced nearly four years later.

1962 - Leaves country secretly. Goes for military training in Morocco and Ethiopia. Returning to South Africa, the Black Pimpernel is captured and sentenced to five years for incitement and illegally leaving the country.

1963 - While serving five-year sentence, Mandela is charged with conspiracy and sabotage.

June 12, 1964 - Mandela and seven others are sentenced to life imprisonment on Robben Island, off Cape Town.

Feb. 2, 1990 - FW de Klerk, South Africa's last white president, lifts ban from ANC and other liberation movements. Mandela is freed on Feb. 11.

1991 - Elected president of the ANC.

Oct. 1993 - Wins Nobel Peace Prize with de Klerk.

May 10, 1994 - Mandela is inaugurated as South Africa's first black president.

Dec. 1997 - Hands leadership of ANC to Deputy President Thabo Mbeki in first stage of phased transfer of power.

July 18, 1998 - Marks 80th birthday with marriage to Graca Machel, widow of Mozambican President Samora Machel.

June 16, 1999 - Retires, hands power to Mbeki.

June 1, 2004 - Announces he will cut back public schedule.

Jan. 6, 2005 - Announces that only surviving son Makgatho Mandela has died from AIDS at the age of 54.

Nov. 1, 2006 - Mandela receives Amnesty International's 2006 Ambassador of Conscience award for being a moral guide in a world plagued by human rights abuses. July 18, 2007 - Launches an international group of elder statesmen, to tackle world problems including climate change, HIV/AIDS and poverty.

Aug. 29, 2007 - Britain honours Mandela by unveiling a bronze statue alongside Winston Churchill and Abraham Lincoln in London's Parliament Square.

June 25, 2008 - Mandela uses a speech at a dinner in London to condemn a tragic failure of leadership in Zimbabwe.

June 26, 2008 - U.S. lawmakers erase references to Mandela as a terrorist from national databases. June 27, 2008 - Stars pay tribute to Mandela, celebrating his 90th birthday, in London's Hyde Park.

May 9, 2009 - Mandela attends Jacob Zuma's presidential inauguration ceremony, in a huge political coup for Zuma.

Aug. 7, 2009 - U.S. Secretary of State Hillary Clinton meets Mandela and gets a private viewing of his archives, saying it was a treasure trove of lessons for future generations.

Dec. 11, 2009 - The film Invictus opens in the United States. It is the story of how Mandela brought the 1995 Rugby World Cup Championship to his nation, utilizing the South African team around which to rally his countrymen and ease racial tensions between black and white citizens.