Central Africa is a fertile area, rich in mineral deposits. Here a number of states emerged with sophisticated metal working techniques after 1000 AD in what is referred to as the ‘late iron age.’ To the East, between the rivers Zambezi and Limpopo, the grassland zone was rich in cattle, and gold. A distinctive and elaborate form of pottery was made. By the 13th century an empire known as Great Zimbabwe emerged, which left stone ruins of what must have been a spectacular fortified palace.
By the 15th century this empire had collapsed, taken over by the Mutapa rulers. The Portuguese appeared around the same time attracted by gold and slaves. They made commercial inroads across the width of southern Africa, from what is now Angola in the West, to Mozambique in the East.
They came across a number of power kingdoms. Among them: the Kongo in the West (present day northern Angola and part of DR Congo); the decentralised and flexible state of Lunda in the centre; and the Lundu Kingdom in the east, which cultivated the cassava and maize which the Portuguese imported with great success.
Also in the East, was Monumutapa, under Mutapa rule, which resisted all attempts by the Portuguese at subjugation. Reduced in size, it maintained its vigour under the military dynasty of Changamires. By contrast the Kongo Empire was, by the 17th century, devastated by the slave trade.
By the 18th century the slave trade was sufficiently lucrative and brisk at the coast for the Portuguese to have not need to assert their power in any systematic way in the interior. The states and kingdoms of the interior confined their dealings to middlemen in search of ivory, slaves and gold for sale to coastal traders, both African and European.