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MK launched a sabotage campaign against the government, which had recently declared South Africa a republic and withdrawn from the British Commonwealth.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.