Pretoria is South Africa's executive and administrative capital. Pretoria is named after the Voortrekker Leader, General Andries Pretorius. Pretoria - today also called Tshwane - was founded in 1855 and declared the capital of the South African Republic, which was the Boer republic in Transvaal. The president of the republic, Marthinus Pretorius, named it after his father, Andries Pretorius, who had become the national hero of the Voortrekkers after his victory over the Zulu kingdom in the famous battle at Blood River. The founding of Pretoria as the capital of the South African Republic marked the end of the Boers' settlement movements of the Great Trek.
The Union Buildings, the Office of the ---earlier Prime Minister--- but now the State President, was designed by Sir Herbert Baker....
Follow this link to read more about him....http://en.wikipedia.org/wiki/Herbert_Baker
For the first 6 months of the year, the State President spends his office-time in the Union Buildings and the 2nd half of the year...they all "move" to Cape Town for Parliament. There is even a school only for Parliamentary Staff, Ministers and Officials. The area where they all live is called Acacia Park.