Africa north of the Sahara never lost contact with Europe. Greeks traded with ancient Egypt, Carthage with Europe; Rome conquered both sides of the Mediterranean; 8th-century Arab conquest linked Spain and Portugal with North Africa; soon after Spain freed itself from Arab rule, the 16th-century Turks brought most of North Africa under their sway together with Greece and the Balkans.
But most of Africa lay far beyond Europe's horizon until the 15th-century Portuguese explored the whole west coast and reached India round the Cape of Good Hope. They ringed Africa with Portuguese names -- Cape Verde, Lagos, Natal, Beira -- but established themselves in strength only in the Indian Ocean trading ports (the Arabs (30) recaptured these, except Mozambique, around 1700). It was mainly as a route to India that African waters interested them and the other maritime Europeans (in particular Dutch, English and French, though Danes, Swedes and Germans also played their part) who followed and largely superseded them. In Africa itself, even in populous Guinea, the Gold, Ivory and Grain Coasts (the last so named as a source of spices, not cereals) offered little trade until the new plantations in the Americas (M) created a demand for an appalling export commodity: slaves.
Slave trading was a long-established misery of black Africa. A thousand years before the Portuguese sailed south, the first Ghana was exporting slaves to the north across the Sahara, Azania to Arabia, India, even the Far East (E). Later, the Arabs took slaves for over 1,000 years, until the 1880's; and they ravaged the interior from the east coast and from Egypt, raiding halfway across the continent. The Europeans kept to the coast, buying slaves from predatory tribes and states such as Ashanti and Fulani, Dahomey and Benin (C, E, 15, 19, 20). But they thereby encouraged Africans to attack and enslave others on a vast scale; in the late 18th century, 100,000 slaves were shipped across the Atlantic in one year, over a third of them by British slavers.
Resettlement of freed slaves created new coastal communities, and some British colonies originated as bases for naval patrols against slavers after 1807 (17, 18). But in other respects, the end of slaving reduced European interest. There were exceptions: in the 1830's, France colonized Algeria (3), the true course of the Niger was discovered, and many Dutchmen of the Cape colony established in 1652 as a way-station on the route to the Indies trekked far inland to