Why Nations Fail: The Origins of Power, Prosperity, and Poverty

which all laws and customs were distorted and broken to capture slaves and more slaves had devastating effects on political centralization, though in some places it did lead to the rise of powerful states whose main raison d’être was raiding and slaving. The Kingdom of Kongo itself was probably the 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 independentstate 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 twenty-two 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 been at least forty-six to fifty-three million. In fact, it was about one-half of this.
    This massive difference was not only due to about eight million people being exported as slaves from this region between 1700 and 1850, but the millions likely killed by continual internal warfare aimed at capturing slaves. Slavery and the slave trade in Africa further disrupted family and marriage structures and may also have reduced fertility.
    Beginning in the late eighteenth century, a strong movement to abolish the slave trade began to gain momentum in Britain, led by the charismatic figure of William Wilberforce. After repeated failures, in 1807 the abolitionists persuaded the British Parliament to pass a bill making the slave trade illegal. The United States followed with a similar measure the next year. The British government went further, though: it actively sought to implement this measure by stationing naval squadrons in the Atlantic to try to stamp out the slave trade. Though it took some time for these measures to be truly effective, and it was not until 1834 that slavery itself was abolished in the British Empire, the days of the Atlantic slave trade, by far the largest part of the trade, were numbered.
    Though the end of the slave trade after 1807 did reduce the externaldemand for slaves from Africa, this did not mean that slavery’s impact on African societies and institutions would magically melt away. Many African states had become organized around slaving, and the British putting an end to the trade did not change this reality. Moreover, slavery had become much more prevalent within Africa itself. These factors would ultimately shape the path of development in Africa not only before but also after 1807.
    In the place of slavery came “legitimate commerce,” a phrase coined for the export from Africa of new commodities not tied