When Nelson Mandela joined the African National Congress and joined forces against the apartheid movement of the ruling party, he actually believed in non-violence. However, later he joined forces with South African Communist Party. It is then that he co-founded the Umkhonto we Sizwe - a militant group. The group was founded in 1961 and was responsible for bombing government targets. Nelson Mandela was once against arrested in 1962 under the convictions of sabotaging government property and for conspiring the overthrowing of the ruling government. In Rivonia Trial, Mandela was sentenced for life imprisonment.