Answer:
From the seventeenth century on, slaves became the focus of trade between Europe and Africa. Europe’s conquest and colonization of North and South America and the Caribbean islands from the fifteenth century onward created an insatiable demand for African laborers, who were deemed more fit to work in the tropical conditions of the New World. The number of slaves imported across the Atlantic Ocean steadily increased, from approximately 5,000 slaves a year in the sixteenth century to over 100,000 slaves a year by the end of the eighteenth century.
Evolving political circumstances and trade alliances in Africa led to shifts in the geographic origins of slaves throughout the seventeenth and eighteenth centuries. Slaves were generally the unfortunate victims of territorial expansion by imperialist African states or of raids led by predatory local strongmen, and various populations found themselves captured and sold as different regional powers came to prominence. Firearms, which were often exchanged for slaves, generally increased the level of fighting by lending military strength to previously marginal polities. A nineteenth-century tobacco pipe (1977.462.1) from the Democratic Republic of the Congo or Angola demonstrates the degree to which warfare, the slave trade, and elite arts were intertwined at this time. The pipe itself was the prerogative of wealthy and powerful individuals who could afford expensive imported tobacco, generally by trading slaves, while the rifle form makes clear how such slaves were acquired in the first place. Because of its deadly power, the rifle was added to the repertory of motifs drawn upon in many regional depictions of rulers and cultural heroes as emblematic of power along with the leopard, elephant, and python.
The institution of slavery existed in Africa long before the arrival of Europeans and was widespread during the period of economic contact. Private land ownership was largely absent from precolonial African societies, and slaves were one of the few forms of wealth-producing property an individual could possess. Additionally, rulers often maintained corps of loyal, foreign-born slaves to guarantee their political security, and would encourage political centralization by appointing slaves from the imperial hinterlands to positions within the royal capital. Slaves were exported across the desert to North Africa, western Asia, Arabia, and India. However, it would be impossible to argue that transatlantic trade did not have a major effect on the development and scale of slavery in Africa. As the demand for slaves increased with European colonial expansion in the New World, rising prices made the slave trade increasingly lucrative. African states eager to augment their treasuries even preyed upon their peoples by managing their judicial systems, condemning individuals and their families to slavery to reap the rewards of their sale to European traders. Slave exports were responsible for the emergence of several large and powerful kingdoms that relied on a militaristic culture of constant warfare to generate the great numbers of human captives required for trade with the Europeans. The Yoruba kingdom of Oyo on the Guinea coast, founded sometime before 1500, expanded rapidly in the eighteenth century as a result of this commerce. Its formidable army, aided by advanced iron technology, captured immense numbers of slaves that were profitably sold to traders. In the nineteenth century, the aggressive pursuit of slaves through warfare and raiding led to the ascent of the kingdom of Dahomey, in what is now the Republic of Benin, and prompted the emergence of the Chokwe chiefdoms from under the shadow of their Lunda overlords in present-day Angola and the Democratic Republic of the Congo. The Asante kingdom on the Gold Coast of West Africa also became a major slave exporter in the eighteenth century.