Balthazar Johannes "B. J." Vorster was a South African politician who served as the Prime Minister of South Africa from 1966 to 1978 and as the fourth State President of South Africa from 1978 to 1979. Vorster was known for his staunch adherence to apartheid, overseeing the Rivonia Trial in which Nelson Mandela was sentenced to life imprisonment for sabotage, and the Terrorism Act, the complete abolition of non-white political representation, the Soweto Riots and the Steve Biko crisis. He conducted a more pragmatic foreign policy than his predecessors in an effort to improve relations between the white minority government and South Africa's neighbours, particularly after the break-up of the Portuguese colonial empire. Shortly after the Internal Settlement in Rhodesia, in which he was instrumental, he was implicated in the Muldergate Scandal and resigned the premiership in favour of the ceremonial state presidency, which he was forced to give up as well eight months later.