A national convention of white delegates from the four colonies (Natal, the Cape, the Transvaal and the Orange River Colony) meets to discuss union in 1908. The Chief Justice of the Cape Colony is the President of the National Convention. He is none other than Sir Henry de Villiers, brother-in-law of one of Miss Holmes-Orr’s sisters, Sarah. Miss Holmes-Orr and St Mary’s pupils and parents now live in a British dominion and belong to the British Commonwealth of Nations.

The constitution that is drawn up by the delegates is criticised, but nevertheless accepted by both Houses of the British Parliament and by the British monarch; the Union comes into being in 1910.