The Union of South Africa is the historic predecessor to the present-day Republic of South Africa. It came into being on 31 May 1910 with the unification of four previously separate British colonies: Cape Colony, Natal Colony, Transvaal Colony and Orange River Colony. Following World War I, the Union of South Africa was granted the administration of the German South-West Africa colony as a League of Nations mandate and it became treated in most respects as if it were another province of the Union.