The Era of the Atlantic Slave Trade (c. 1470–1860)

The era of the Atlantic slave trade began with the arrival of Portuguese ships on the coast in the late fifteenth century and lasted until the trade was suppressed in the nineteenth century. According to the Library of Congress country study, Portuguese ships reached the Niger Delta by 1471, and in 1481 envoys of the king of Portugal visited the court of the oba of Benin.

Benin traded pepper, ivory and, at first, slaves for coral beads, Indian cloth, European goods and manillas (brass bracelets used as currency), and used firearms bought from the Portuguese to strengthen its position. It later placed an embargo on the export of slaves, and the country study describes it as unique among Nigerian states in refusing to take part in the transatlantic trade, although it kept slaves in its own economy.

Elsewhere the trade grew enormously. The south-western coast and the neighbouring coast of the present Republic of Benin became known to Europeans as the "Slave Coast". After the Portuguese came Dutch, French, English and other traders, and Britain became the leading slaving power in the eighteenth century. The country study estimates that over the whole period more than 3.5 million enslaved people were shipped from Nigeria to the Americas, most of them Igbo and Yoruba, with many Hausa, Ibibio and others; in the nineteenth century perhaps 30 per cent of all those sent across the Atlantic came from Nigeria.

Two powers supplied most of the captives in the eighteenth century. Oyo, whose cavalry pushed south to the coast, grew with the trade and was shaken by struggles between kings and the Oyo Mesi council. In the south-east, the Aro, an Igbo clan whose oracle at Arochukwu was widely consulted, built a network of markets and alliances that fed the ports of Calabar, Bonny and Elem Kalabari, where Efik and Ijaw merchant communities grew into trading towns of 5,000 to 10,000 people.

Britain abolished its own slave trade in 1807 and then used treaties and naval force to suppress it on the coast. The trade nonetheless continued into the nineteenth century, fed by the Yoruba wars that followed Oyo's collapse in the 1820s; the Aro still exported captives through the 1830s.