black nationalist and first black president of South Africa (1994–99). His negotiations in the early 1990s with South African Pres. F.W. de Klerk helped end the country'sapartheid system of racial segregation and ushered in a peaceful transition to majority rule. Mandela and de Klerk were jointly awarded the Nobel Prize for Peace in 1993 for their efforts.

The son of Chief Henry Mandela of the Madiba clan of the Xhosa-speaking Tembu people, Nelson Mandela renounced his claim to the chieftainship to become a lawyer. He attended South African Native College (later the University of Fort Hare) and studied law at the University of the Witwatersrand; he later passed the qualification exam to become a lawyer. In 1944 he joined the African National Congress (ANC), a black-liberation group, and became a leader of its Youth League. That same year he met and married Evelyn Ntoko Mase. Mandela subsequently held other ANC leadership positions, through which he helped revitalize the organization and oppose the apartheid policies of the ruling National Party.

In 1952 in Johannesburg, with fellow ANC leader Oliver Tambo, Mandela established South Africa's first black law practice, specializing in cases resulting from the post-1948 apartheid legislation. Also that year, Mandela played an important role in launching a campaign of defiance against South Africa's pass laws, which required nonwhites to carry documents (known as passes, pass books, or reference books) authorizing their presence in areas that the government deemed “restricted” (i.e., generally reserved for the white population). He traveled throughout the country as part of the campaign, trying to build support for nonviolent means of protest against the discriminatory laws. In 1955 he was involved in drafting the Freedom Charter, a document calling for nonracial social democracy in South Africa. His antiapartheid activism made him a frequent target of the authorities; in March 1956 he was banned (severely restricted in travel, association, and speech), and in December he was arrested with more than 100 other people on charges of treason that were designed to harass antiapartheid activists. Mandela went on trial that same year and eventually was acquitted in 1961. During the extended court proceedings, he divorced his first wife and married Nomzamo Winifred Madikizela (Winnie Madikizela-Mandela).

After the massacre of unarmed black South Africans by police forces at Sharpeville in 1960 and the subsequent banning of the ANC, Mandela abandoned his nonviolent stance and began advocating acts of sabotage against the South African regime. He went underground (during which time he became known as the Black Pimpernel for his ability to evade capture) and was one of the founders of Umkhonto we Sizwe (“Spear of the Nation”), the military wing of the ANC. In 1962 he went to Algeria for training in guerrilla warfare and sabotage, returning to South Africa later that year. On August 5, shortly after his return, Mandela was arrested at a road block in Natal; he was subsequently sentenced to five years in prison.

In October 1963 the imprisoned Mandela and several other men were tried for sabotage, treason, and violent conspiracy in the infamous Rivonia Trial, named after a fashionable suburb of Johannesburg where raiding police had discovered quantities of arms and equipment at the headquarters of the underground Umkhonto we Sizwe. Mandela's speech from the dock, in which he admitted the truth of some of the charges made against him, was a classic defense of liberty and defiance of tyranny. (His speech garnered international attention and acclaim and was published later that year as I Am Prepared to Die.) On June 12, 1964, he was sentenced to life imprisonment, narrowly escaping the death penalty.

From 1964 to 1982 Mandela was incarcerated at Robben Island Prison, off Cape Town. He was subsequently kept at the maximum-security Pollsmoor Prison until 1988, when, after being treated for tuberculosis, he was transferred to Victor Verster Prison near Paarl. The South African government periodically made conditional offers of freedom to Mandela, most notably in 1976, on the condition that he recognize the newly independent—and highly controversial—status of the Transkei Bantustan and agree to reside there. An offer made in 1985 required that he renounce the use of violence. Mandela refused both offers, the second on the premise that only free men were able to engage in such negotiations and, as a prisoner, he was not a free man.

Throughout his incarceration, Mandela retained wide support among South Africa's black population, and his imprisonment became a cause célèbre among the international community that condemned apartheid. As South Africa's political situation deteriorated after 1983, and particularly after 1988, he was engaged by ministers of Pres. P.W. Botha's government in exploratory negotiations; he met with Botha's successor, de Klerk, in December 1989.

On Feb. 11, 1990, the South African government under President de Klerk released Mandela from prison. Shortly after his release, Mandela was chosen deputy president of the ANC; he became president of the party in July 1991. Mandela led the ANC in negotiations with de Klerk to end apartheid and bring about a peaceful transition to nonracial democracy in South Africa.

In April 1994 the Mandela-led ANC won South Africa's first elections by universal suffrage, and on May 10 Mandela was sworn in as president of the country's first multiethnic government. He established in 1995 the Truth and Reconciliation Commission (TRC), which investigated human rights violations under apartheid, and he introduced housing, education, and economic development initiatives designed to improve the living standards of the country's black population. In 1996 he oversaw the enactment of a new democratic constitution. Mandela resigned his post with the ANC in December 1997, transferring leadership of the party to his designated successor, Thabo Mbeki. Mandela and Madikizela-Mandela had divorced in 1996, and in 1998 Mandela married Graca Machel, the widow of Samora Machel, the former Mozambican president and leader of Frelimo.

Mandela did not seek a second term as South African president and was succeeded by Mbeki in 1999. After leaving office Mandela retired from active politics but maintained a strong international presence as an advocate of peace, reconciliation, and social justice, often through the work of the Nelson Mandela Foundation, established in 1999. He was a founding member of the Elders, a group of international leaders established in 2007 for the promotion of conflict resolution and problem solving throughout the world. In 2008 Mandela was feted with several celebrations in South Africa, Great Britain, and other countries in honour of his 90th birthday.

Mandela Day, observed on Mandela's birthday, was created to honour his legacy by promoting community service around the world. It was first observed on July 18, 2009, and was sponsored primarily by the Nelson Mandela Foundation and the 46664 initiative (the foundation's HIV/AIDS global awareness and prevention campaign); later that year the United Nations declared that the day would be observed annually as Nelson Mandela International Day.

Mandela's writings and speeches were collected in I Am Prepared to Die (1964; rev. ed. 1986), No Easy Walk to Freedom (1965; updated ed. 2002), The Struggle Is My Life (1978; rev. ed. 1990), and In His Own Words (2003). His autobiography, Long Walk to Freedom, was published in 1994.