Nelson Mandela was a South African anti-apartheid revolutionary and politician who served as President of South Africa from 1994 to 1999. He was imprisoned for 27 years for his activism against apartheid but was released in 1990 amid international pressure. As president, he established a new constitution and held South Africa's first free elections, helping establish a multi-racial democracy. Throughout his life, Mandela worked to end apartheid through nonviolent protest and, later, armed resistance from the African National Congress. Even after retiring from politics, he continued philanthropic work focused on combating poverty and HIV/AIDS.