first African state to experience a metamorphosis into a slaving state, until it was destroyed by civil war. Other slaving states arose most prominently in West Africa and included Oyo in Nigeria, Dahomey in Benin, and subsequently Asante in Ghana.
The expansion of the state of Oyo in the middle of the seventeenth century, for example, is directly related to the increase of slave exports on the coast. The state’ s power was the result of a military revolution that involved the import of horses from the north and the formation of a powerful cavalry that could decimate opposing armies. As Oyo expanded south toward the coast, it crushed the intervening polities and sold many of their inhabitants for slaves. In the period between 1690 and 1740, Oyo established its monopoly in the interior of what came to be known as the Slave Coast. It is estimated that 80 to 90 percent of the slaves sold on the coast were the result of these conquests. A similar dramatic connection between warfare and slave supply came farther west in the eighteenth century, on the Gold Coast, the area that is now Ghana. After 1700 the state of Asante expanded from the interior, in much the same way as Oyo had previously. During the first half of the eighteenth century, this expansion triggered the so-called Akan Wars, as Asante defeated one independent state after another. The last, Gyaman, was conquered in 1747. The preponderance of the 375,000 slaves exported from the Gold Coast between 1700 and 1750 were captives taken in these wars.
Probably the most obvious impact of this massive extraction of human beings was demographic. It is difficult to know with any certitude what the population of Africa was before the modern period, but scholars have made various plausible estimates of the impact of the slave trade on the population. The historian Patrick Manning estimates that the population of those areas of West and West-Central Africa that provided slaves for export was around twentytwo to twenty-five million in the early eighteenth century. On the conservative assumption that during the eighteenth and early nineteenth centuries these areas would have experienced a rate of population growth of about half a percent a year without the slave trade, Manning estimated that the population of this region in 1850 ought to have