Short answers, pulled from the story.
Nelson Mandela was a South African anti-apartheid activist, statesman and revolutionary who became the first president of South Africa, serving from 1994 to 1999. He was the country's first Black head of state and the first elected in a fully representative democratic election.
Nelson Mandela was born on the 18th of July 1918, in the village of Mvezo, then part of South Africa's Cape Province. He was born into the Thembu royal family and given the forename Rolihlahla, a Xhosa term colloquially meaning "troublemaker".
Nelson Mandela served 27 years in prison. He was sentenced to life imprisonment after the Rivonia Trial on the 12th of June 1964, spent 18 years on Robben Island, and was released from Victor Verster Prison on the 11th of February 1990.
Nelson Mandela was found guilty in the Rivonia Trial of sabotage and conspiracy to violently overthrow the government. He had co-founded the militant Umkhonto we Sizwe in 1961, which led a sabotage campaign against the apartheid government.
As president, Nelson Mandela focused on national reconciliation and dismantling the legacy of apartheid. He led a Government of National Unity, created the Truth and Reconciliation Commission chaired by Desmond Tutu, and expanded housing, electricity, healthcare and welfare for the black majority.
Madiba is Nelson Mandela's Thembu clan name, and he is often referred to by it within South Africa, where he is also described as the "Father of the Nation". He received more than 250 honours, including the Nobel Peace Prize.