STONE-USING PEOPLES HAD PIONEERED THE COLONISATION OF AFRICA. THEIR successors carried it forward with the aid of metals: first copper and bronze, then iron. Only northern Africa had a bronze age; agriculturalists used iron to colonise most of eastern and southern Africa.
The earliest evidence of metalworking in Africa comes from southern Egypt late in the fifth millennium bc. At first pure natural copper was probably used to make pins, piercing instruments, and other small articles. Smelting of copper ore to remove impurities probably began in the first half of the fourth millennium, either invented locally or imported from western Asia. It caused no discontinuity in Egyptian history, for stone tools were widely used until the first millennium bc, but the new technique spread until a fixed weight of copper became Egypt's standard unit of value. Moreover, the innovation coincided closely with the creation of Africa's first great agricultural civilisation in the Nile Valley. It was an African civilisation, for Egypt's peoples, although heterogeneous, contained a core of Afro-Mediterranean race and spoke an Afroasiatic language. Egyptian civilisation displayed many cultural and political patterns later to appear elsewhere in the continent, although Egypt also illuminated wider African history by means of contrast.
The contrast was rooted in the environment. Pioneers had practised agriculture in the Fayum depression and on the southwestern edge of the Nile Delta since about 5200 bc. During the following millennium, desiccation drove others from the eastern Sahara to settle on ridges bordering the Nile Valley, where lower floods made land available for pastoralism and agriculture. Dependence on the river made these settlers more amenable to political control than Africans who retained their ancient freedom of movement. During the fourth millennium bc, both Lower Egypt (the Delta) and Upper Egypt (the narrow valley southwards to Aswan) practised a culture characterised by exploitation of the floodwaters, use of copper as well as flint, weaving of linen cloth, trade with southwestern Asia, temples dedicated to deities like Horus and Seth (later prominent in the Egyptian pantheon), a social stratification displayed by the plain graves of commoners and the elaborate painted