The Iron Age
Around 3,000BC, late Stone-Age hunter-gatherer groups in Ethiopia, and elsewhere in north and west Africa, started to keep domestic animals, sow seeds, and harvest the produce: they became the world's first farmers.
By around 1,000BC these new pastoral practices had spread south into the equatorial forests of what is now the Democratic Republic of Congo, to around Lake Victoria, and into the northern area of the Great Rift Valley, in northern Tanzania. However, agriculture did not spread south into the rest of central/southern Africa immediately. Only when the technology, and the tools, of iron-working became known did the practices start their relentless expansion southwards.
The spread of agriculture and Iron-Age culture seems to have been rapid. It was brought south by Africans who were taller and heavier than the existing small inhabitants. The ancestors of the San/Bushmen people, with their simple Stone-Age technology and hunter-gatherer existence, just could not compete with these Iron-Age farmers, who became the ancestors of virtually all the modern black Africans in southern Africa.
This major migration occurred around the first few centuries AD, and since then the San/Bushmen of southern Africa have gradually been either assimilated into the migrant groups, or effectively pushed into the areas which could not be farmed. Thus the older Iron-Age cultures persisted in the forests of the north and east of Zambia – which were more difficult to cultivate – much longer than they survived in the south of the country.
By the 4th or 5th century AD, Iron-Age farmers had settled throughout much of southern Africa. As well as iron-working technology, they brought with them pottery, the remains of which are used by archaeologists to work out the migrations of various different groups of these Bantu settlers. These migrations continued, and the distribution of pottery styles suggests that the groups moved around within the subcontinent: this was much more complex than a simple north-south influx.