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MK launched a sabotage campaign against the government, which had recently declared South Africa a republic and withdrawn from the British Commonwealth.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 abroad 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 was found implicating Mandela and other activists, who were brought to stand trial for sabotage, treason and violent conspiracy alongside their associates.