The most important development in West Africa before the European conquest was the decline of the Atlantic slave trade and the simultaneous rise in exports of palm oil and other commodities. This shift in African foreign trade marked the beginning of modern economic development in sub-Saharan Africa.

Although the trade in enslaved Africans was a global phenomenon, the transatlantic slave trade between Africa and the Americas became the most extensive and significant portion of it (see “The Transatlantic Slave Trade” in Chapter 20). After 1775 a broad campaign to abolish slavery, in which British women played a critical role, developed in Britain and grew into one of the first peaceful mass political movements based on the mobilization of public opinion in British history. Abolitionists also argued for a transition to legitimate (nonslave) trade, to end both the transatlantic slave trade and the internal African slave systems. In 1807 Parliament declared the slave trade illegal. Britain then established the antislavery West Africa Squadron, using its navy to seize slave runners’ ships, liberate the captives, and settle them in the British port of Freetown, in Sierra Leone, as well as in Liberia (see Map 25.1). Freed American slaves had established the colony of Liberia in 1821–1822.

British action had a limited impact at first. Britain’s West Africa Squadron intercepted fewer than 10 percent of all slave ships, and the demand for slaves remained high on the expanding and labor-intensive sugar and coffee plantations of Cuba and Brazil until the 1850s and 1860s. In the United States, President Thomas Jefferson signed into law an act that banned slave importation from January 1, 1808. From that time on, natural increase (slaves having children) mainly accounted for the subsequent growth of the African American slave population before the Civil War. Strong financial incentives remained, however, for Portuguese and other European slave traders and for those African rulers who relied on profits from the trade for power and influence.

As more nations joined Britain in outlawing the slave trade, shipments of human cargo slackened along the West African coast (see Map 25.1). At the same time the ancient but limited shipment of slaves across the Sahara and from the East African coast into the Indian Ocean and through the Red Sea expanded dramatically. Only in the 1860s did this trade begin to decline rapidly. As a result of these shifting currents, total slave exports from all regions of sub-Saharan Africa declined only marginally. Abolitionists failed to achieve their vision of “legitimate” commerce in tropical products quickly replacing illegal slave exports.

Nevertheless, beginning in West Africa, trade in tropical products did make steady progress for several reasons. First, with Britain encouraging palm tree cultivation as an alternative to the slave trade, palm oil sales from West Africa to Britain surged. Second, the sale of palm oil admirably served the self-interest of industrializing Europe. Manufacturers used palm oil to lubricate their giant machines and to make cheap soap and other cosmetics. Third, peanut production for export also grew rapidly, in part because both small, independent African family farmers and large-scale enterprises could produce peanuts for the substantial American and European markets.

Finally, powerful West African rulers and warlords who had benefited from the Atlantic slave trade redirected some of their slaves’ labor into the production of legitimate goods for world markets. This was possible because local warfare and slave raiding continued to enslave large numbers of people in sub-Saharan Africa, so slavery and slave markets remained strong. Although some enslaved captives might still be sold abroad, now women were often kept as wives, concubines, or servants, while men were used to transport goods, mine gold, grow crops, and serve in slave armies. Thus, the transatlantic slave trade’s slow decline coincided with the most intensive use of slaves within Africa.

All the while, a new group of African merchants was emerging to handle legitimate trade, and some grew rich. Women were among the most successful of these merchants. There is a long tradition of West African women being actively involved in trade (see “Impact on African Societies” in Chapter 20), but the arrival of Europeans provided new opportunities. The African wife of a European trader served as her husband’s interpreter and learned all aspects of his business. If the husband died, the African wife inherited his commercial interests, including his inventory and his European connections. Many such widows used their considerable business acumen to make small fortunes.

By the 1850s and 1860s legitimate African traders, flanked by Western-educated African lawyers, teachers, and journalists, had formed an emerging middle class in the West African coastal towns. Unfortunately for West Africans, in the 1880s and 1890s African business leadership gave way to imperial subordination.