This chapter explains why, where, and when regions of sub-Saharan Africa became the hunting grounds for the slaves of Christian and Muslim empires. It rejects the Nieboer–Domar hypothesis that low population density explains an African “tradition” of slavery that Europeans tapped into. It also rejects the hypothesis that the tsetse fly did the same. Evidence supports the hypothesis that the tsetse fly and soil erosion from tropical downpour produced pockets of poverty by constraining the development of animal-based agriculture. International slave trades “attacked” these pockets of poverty and left behind slavery as an institution. An alternative to constrained agriculture was gold mining. Sub-Saharan Africa was a major world exporter of gold until large deposits were discovered in eighteenth-century Brazil. The international purchasing power of African gold provides a long view of economic development in gold-exporting regions of Africa: A Golden Age (from the fourteenth to the sixteenth century), an Age of Trade (the seventeenth century), and an Age of Slavery (eighteenth and nineteenth centuries).