If diamonds had begun the transformation of southern Africa, the industrialisation which followed the discovery of vast seams of underground gold on the Witwatersrand in 1886, followed by the renewed assertion of British supremacy in the interior of southern Africa, greatly accelerated the forces making for change over the entire region, and set the pace for much of the twentieth century. In the 1880s the sub-continent was still composed of a cluster of independent African kingdoms and Afrikaner republics, British colonies and protectorates; the huge new German acquisition of South West Africa was still largely unconquered. By 1910, with the political unification of the South African colonies, British ambitions of creating a southern African confederation seemed well on the way to fulfilment, while, to the north, British imperial frontiers stopped short only at Katanga and Tanganyika. All over southern African the annexation of African polities meant the establishment of colonial states, with government departments and courts, alien soldiers and policemen. By 1910 railroad arteries, often built at enormous human cost, connected the coast with mining centres as far afield as Bwana Mkubwa and Elisabethville (Lubumbashi), opening up new markets and releasing new sources of labour. Boundaries had been drawn which were to last beyond the colonial period, and it was accepted by the colonial rulers that the Zambezi was to be the boundary between the ‘white south’ and the ‘tropical dependencies’ of east and central Africa, although British Central Africa uneasily straddled the divide.