By the late 19th century, the limitations of the Cape's liberal tradition were becoming apparent. The hardening of racial attitudes that accompanied the rise of a more militant imperialist spirit coincided locally with the watershed discovery of mineral riches in the interior of southern Africa. In a developing economy, cheap labor was at a premium, and the claims of educated Africans for equality met with increasingly fierce resistance.
At the same time, the large numbers of Africans in the chiefdoms beyond the Kei River and north of the Gariep (Orange River), then being incorporated into the Cape Colony, posed new threats to racial supremacy and white security, increasing segregationist pressures.
Alluvial diamonds were discovered on the Vaal River in the late 1860s. The subsequent discovery of dry deposits at what became the city of Kimberley drew tens of thousands of people, black and white, to the first great industrial hub in Africa, and the largest diamond deposit in the world. In 1871, the British, who ousted several rival claimants, annexed the diamond fields, which fell in sparsely populated territory to the west of the main corridors of northward migration.
The Colony of Griqualand West thus created was incorporated into the Cape Colony in 1880. By 1888, the consolidation of diamond claims had led to the creation of the huge De Beers monopoly under the control of Cecil Rhodes. He used his power and wealth to become Prime Minister of the Cape Colony (1890 1896) and, through his chartered British South Africa Company, conqueror and ruler of modern-day Zambia and Zimbabwe.
The mineral discoveries had a major impact on the subcontinent as a whole. A railway network linking the interior to the coastal ports revolutionized transportation and energized agriculture. Coastal cities such as Cape Town, Port Elizabeth, East London and Durban experienced an economic boom as port facilities were upgraded.
The fact that the mineral discoveries coincided with a new era of imperialism and the scramble for Africa brought imperial power and influence to bear in southern Africa as never before.
Independent African chiefdoms were systematically subjugated and incorporated by their white-ruled neighbors. The most dramatic example was the Zulu War of 1879, which saw the Zulu State brought under imperial control, during which King Cetshwayo's impis inflicted a celebrated defeat on British forces at Isandlwana.
In 1897, Zululand was incorporated into Natal. The South African Republic (Transvaal) was annexed by Britain in 1877. Boer resistance led to British withdrawal in 1881, but not before the Pedi (northern Sotho) State which fell within the Republic's borders had been subjugated. The indications were that, having once been asserted, British hegemony was likely to be reasserted.
The southern Sotho and Swazi territories were also brought under British rule but maintained their status as imperial dependencies, so that both the current Lesotho and Swaziland escaped the rule of local white regimes.
The discovery of the Witwatersrand goldfields in 1886 was a turning point in the history of South Africa. It presaged the emergence of the modern South African industrial State.
Once the extent of the reefs had been established, and deep-level mining had proved to be a viable investment, it was only a matter of time before Britain and its local representatives again found a pretext for war against the Boer republics of Transvaal and the Orange Free State.
The demand for franchise rights for English-speaking immigrants on the gold-fields (the Uitlanders) provided a lever for applying pressure on the government of President Paul Kruger.
Egged on by the deep-level mining magnates, to whom the Boer government seemed obstructive and inefficient, and by the expectation of an Uitlander uprising, Rhodes launched a raid into the Transvaal in late December 1895.
The raid's failure saw the end of Rhodes' political career, but Sir Alfred Milner, British High Commissioner in South Africa from 1897, was determined to overthrow Kruger's government and establish British rule throughout the subcontinent. The Boer Government was eventually forced into a declaration of war in October 1899.
The mineral discoveries had a radical impact on every sphere of society. Labor was required on a massive scale and could only be provided by Africans, who had to be drawn away from the land.
Many Africans did respond with alacrity to the opportunities presented by wage labor, traveling long distances to earn money to supplement rural enterprise in the homestead economy.
In response to the expansion of internal markets, Africans exploited their farming skills and family labor to good effect to increase production for sale. A substantial black peasantry arose, often by means of share-cropping or labor tenantry on white-owned farms.
For the white authorities, however, the chief consideration was ensuring a labor supply and undermining black competition on the land. Conquest, land dispossession, taxation and pass laws were designed to force black men off the land and channel them into labor markets, especially to meet the needs of the mines.
Gradually, the alternatives available to them were closed, and the decline of the homestead economy made wage labor increasingly essential for survival.
The integration of Africans into the emerging urban and industrial society of South Africa should have followed these developments, but short-term, recurrent labor migrancy suited employers and the authorities, which sought to entrench the system.
The closed compounds pioneered on the diamond fields, as a means of migrant labor control, were replicated at the gold-mines. The preservation of communal areas from which migrants could be drawn had the effect of lowering wages by denying Africans rights within the urban areas and keeping their families and dependants on subsistence plots in the reserves.
Africans could be denied basic rights if the fiction could be maintained that they did not belong in 'white South Africa' but to 'tribal societies' from which they came to service the 'white man's needs'. Where black families secured a toehold in the urban areas, local authorities confined them to segregated 'locations'. This set of assumptions and policies informed the development of segregationist ideology and, later (from 1948), apartheid.