While in the west of the country white trekboers were migrating from the Cape Colony, in the east equally significant movements were under way. Throughout the seventeenth and eighteenth centuries, descendants of the first Bantu speakers to penetrate into South Africa had been swelling their numbers and had expanded right across the eastern half of the country, where the rainfall was high enough for their mixed farming economy. By the turn of the nineteenth century, the territory was brimming with people and cattle who were fast grazing it out, the limits of expansion having been reached. Exacerbating this was a sustained period of drought.

 

Nowhere was this more marked than in KwaZulu-Natal , where chiefdoms survived by subduing and absorbing their neighbours to gain control of pasturage, thus creating larger and more powerful groupings. By the early part of the nineteenth century, two chiefdoms, the Ndwandwe and the Mthethwa , dominated the eastern section of South Africa around the Tugela River. During the late 1810s a major confrontation between them ended in the defeat of the Mthethwa.

Out of their ruins emerged the Zulus , who were to become one of the most powerful polities in southern Africa. Prior to the defeat of the Mthethwa, the Zulus had been a minor clan under their domination. Around 1816, Shaka assumed the chieftaincy of the Zulus, whose fighting tactics he quickly transformed, supplementing the Nguni's traditional long javelin with the assegai , a short stabbing spear suitable for close combat. The throwing spear rendered a warrior unarmed once he had thrown it and was relatively easily deflected by a cowhide shield, but with a stabbing spear he could keep on fighting indefinitely. Shaka also introduced the tactic known as the "horns of the bull" by which the enemy were outflanked by highly disciplined formations spreading out to engulf them by means of two wings. The manoeuvre was used to devastating effect against the British at the Battle of Isandlwana in 1879.

By 1820, the Zulus had incorporated the fragments of the Mthethwa and had defeated the Ndwandwe. By the middle of the decade they had formed a centralized military state with a 40,000-strong standing army. The nature of war in the east changed from the almost symbolic skirmishes that characterized Nguni raids up to the end of the eighteenth century to decisive battles in which massacres of women and children weren't unknown. Nevertheless, the real strength of the system lay in its ability to absorb the survivors, who became members of the expanding Zulu state. Throughout the 1820s, Shaka sent out his armies to attack his neighbours and take their cattle. In 1828, in a palace coup, he was stabbed to death by a servant and his two half-brothers, one of whom, Dingane , succeeded him. Dingane continued with his brother's ruthless policies and tactics.

The rise of the Zulu state reverberated right across southern Africa and led to the creation of a series of centralized Nguni states as well as paving the way for Boer expansion into the interior. In a movement known as the mfecane , or forced migrations, huge areas of the country were laid waste and people across eastern South Africa were displaced, dispossessed and driven off their lands, either attempting to survive in small groups or banding together in larger political organizations to survive. To the north of the Zulu kingdom, another Nguni group with strong cultural and linguistic affinities with the Zulus came together under Sobhuza I and his son Mswati II, after whom their new state Swaziland took its name. A few hundred Zulus under the leadership of Mzilikazi had taken refuge in Northwest Province after rebelling against Shaka. By 1829, their numbers had swelled to around seventy thousand, but in 1838 they were routed by encroaching Voortrekkers, against whose firearms they proved no match. They relocated to southwestern Zimbabwe, where they re-established themselves as the Matabele kingdom. In the Drakensberg, on the west flank of KwaZulu-Natal, Moshoeshoe I , another chief with humble origins, used diplomacy and cunning to build up his state from the ruins of the mfecane . By providing a haven to refugees, he was able to build up a substantial state from disparate Sotho groupings. Believing that "peace is like the rain which makes the grass grow", he kept no standing army, relying instead on opportunism and good-neighbourliness to survive.