<Tr> <Td_colspan="4"> Tried to cut ties with United Kingdom . Removal of Coloured voters from the common voters roll . Extended' treason trial' of 156 activists (including Nelson Mandela) involved in the Freedom Charter . Severed diplomatic relations with the Soviet Union . Died in office . </Td> </Tr> <Tr> <Th> 6 </Th> <Td> Hendrik Frensch Verwoerd (1901--1966) </Td> <Td> </Td> <Td> 2 September 1958 </Td> <Td> 6 September 1966 </Td> <Td>--(12th) 1961 (13th) 1966 (14th) </Td> <Td> National Party </Td> </Tr> <Tr> <Td_colspan="4"> Start of the South African Border War . The Wind of Change speech by British PM Harold Macmillan . Proclaimed South Africa a Republic after 1960 referendum . Abolished the separate Black voters roll . Launched the bantustan programme . Assassinated . </Td> </Tr> <Tr> <Th> 7 </Th> <Td> Balthazar Johannes Vorster (1915--1983) </Td> <Td> </Td> <Td> 13 September 1966 </Td> <Td> 2 October 1978 </Td> <Td>--(14th) 1970 (15th) 1974 (16th) 1977 (17th) </Td> <Td> National Party </Td> </Tr>

Who was the first black prime minister of south africa