This essay attempts to show how the Social Darwinist thinking of white racial superiority, and so, ultimately, white supremacy, came to be institutionalised in law in South Africa. It looks specifically at the making and institutionalisation of the School Board Act (SBA) of 1905 of the Colony of the Cape of Good Hope. It argues that the SBA contains one of the first constitutive moves that are made in the South Africa that is to emerge with the Act of Union in 1910 with respect to classification, ranking, and ordering in the country's long history of race-making. It precedes better-known pieces of legislation such as the Population Registration Act of 1950 which the apartheid government institutes almost 50 years later. Through the SBA, "race" as a social fact is entrenched in legal and juridical terms. The essay examines how this process is institutionalised through legal judgements provided by the courts of the Cape Colony.