In 1961, Nelson Mandela co-founded and became the first leader of Umkhonto we Sizwe ("Spear of the Nation"), also known as MK, a new armed wing of the ANC. Under Mandela's leadership, MK launched a sabotage campaign against the government, which had recently declared South Africa a republic and withdrawn from the British Commonwealth. In January 1962, Mandela traveled aboard illegally to attend a conference of African nationalist leaders in Ethiopia, visit the exiled Oliver Tambo in London and undergo guerilla training in Algeria. On August 5, shortly after his return, he was arrested and subsequently sentenced to five years in prison for leaving the country and inciting a 1961 workers strike. The following July, police raided an ANC hideout in Rivonia, a suburb on the outskirts of Johannesburg, and arrested a racially diverse group of MK leaders who had gathered to debate the merits of a guerilla insurgency. Evidence eas found implicating Mandela and other activists, who were brought to stand trial for sabotage, treason and violent conspiracy alongside their associates.Mandela and other seven defendants narrowly escaped the gallows and were instead sentenced to life imprisonment during the so-call Rivonia Trial, which lasted eight months and attracted substantial international attention. In a stirring opening statement that sealed his iconic status around the world, Mandela admitted to some of the charges against him while defending the ANC's actions and denouncing the injustices of apartheid.