During the Napoleonic Wars, the Cape Colony was annexed by the British and officially became their colony in 1815. Britain encouraged settlers to the Cape, and in particular, sponsored the 1820 Settlers to farm in the disputed area between the colony and the Xhosa in what is now the Eastern Cape. The changing image of the Cape from Dutch to British excluded the Dutch farmers in the area, the Boers who in the 1820s started their Great Trek to the northern areas of modern South Africa. This period also marked the rise in power of the Zulu under their king Shaka Zulu. Subsequently, several conflicts arose between the British, Boers and Zulus, which led to the Zulu defeat and the ultimate Boer defeat in the Second Anglo-Boer War. However, the Treaty of Vereeniging established the framework of South African limited independence as the Union of South Africa. British colonization At the tip of the continent, the British found an established colony with 25,000 slaves, 20,000 white colonists, 15,000 Khoisan, and 1,000 freed black slaves. Power resided solely with a white élite in Cape Town, and differentiation on the basis of race was deeply entrenched. Outside Cape Town and the immediate hinterland, isolated black and white pastoralists populated the country. Like the Dutch before them, the British initially had little interest in the Cape Colony, other than as a strategically located port. As one of their first tasks they tried to resolve a troublesome border dispute between the Boers and the Xhosa on the colony's eastern frontier. In 1820 the British authorities persuaded about 5,000 middle-class British immigrants (most of them "in trade") to leave England behind and settle on tracts of land between the feuding groups with the idea of providing a buffer zone. The plan was singularly unsuccessful. Within three years, almost half of these 1820 Settlers had retreated to the towns, notably Grahamstown and Port Elizabeth, to pursue the jobs they had held in Britain. While doing nothing to resolve the border dispute, this influx of settlers solidified the British presence in the area, thus fracturing the relative unity of white South Africa. Where the Boers and their ideas had before gone largely unchallenged, European Southern Africa now had two language groups and two cultures. A pattern soon emerged whereby English-speakers became highly urbanised, and dominated politics, trade, finance, mining, and manufacturing, while the largely uneducated Boers were