Slavery, though abundantly practiced in Africa itself and widespread in the ancient Mediterranean world, had nearly died out in medieval Europe. It was revived by the Portuguese in Prince Henry’s time, beginning with the enslavement of Berbers in 1442. Portugal populated Cape Verde, Fernando Po (now Bioko), and São Tomé largely with Black slaves and took many to the home country, especially to the regions south of the Tagus River.

New World Black slavery began in 1502, when Gov. Nicolás de Ovando of Hispaniola imported a few evidently Spanish-born Blacks from Spain. Rapid decimation of the Indian population of the Spanish West Indies created a labour shortage, ultimately remedied from Africa. The great reformer, Las Casas, advocated importation of Blacks to replace the vanishing Indians, and he lived to regret having done so. The population of the Greater Antilles became largely Black and mulatto; on the mainland, at least in the more populated parts, the Indians, supplemented by a growing mestizo caste that clung more tenaciously to life and seemed more suited to labour, kept African slavery somewhat confined to limited areas.

The Portuguese at first practiced Indian slavery in Brazil and continued to employ it partially until 1755. It was gradually replaced by the African variety, beginning prominently in the 17th century and coinciding with the rapid rise of Brazilian sugar culture.

As the English, French, Dutch, and, to a lesser extent, the Danes colonized the smaller West Indian islands, these became plantation settlements, largely cultivated by Blacks. Before the latter arrived in great numbers, the bulk of manual labour, especially in the English islands, was performed by poor whites. Some were indentured, or contract, servants; some were redemptioners who agreed to pay ship captains their passage fees within a stated time or be sold to bidders; others were convicts. Some were kidnapped, with the tacit approval of the English authorities, in keeping with the mercantilist policy that advocated getting rid of the unemployed and vagrants. Black slavery eventually surpassed white servitude in the West Indies.

John Hawkins commanded the first English slave-trading expedition in 1562 and sold his cargo in the Spanish Indies. English slaving, nevertheless, remained minor until the establishment of the English island colonies in the reign of James I (ruled 1603–25). A Dutch captain sailed the first cargo of Black slaves to Virginia in 1619, the year in which the colony exported 20,000 pounds (9,000 kilograms) of tobacco. The restored Stuart king, Charles II, gave English slave trade to a monopolistic company, the Royal Adventurers Trading to Africa, in 1663, but the Adventurers accomplished little because of the early outbreak of war with Holland (1665). Its successor, the Royal African Company, was founded in 1672 and held the English monopoly until 1698, when all Englishmen received the right to trade in slaves. The Royal African Company continued slaving until 1731, when it abandoned slaving in favour of traffic in ivory and gold dust. A new slaving company, the Merchants Trading to Africa (founded 1750), had directors in London, Liverpool, and Bristol, with Bristol furnishing the largest quota of ships, estimated at 237 in 1755. Jamaica offered the greatest single market for slaves and is believed to have received 610,000 between 1700 and 1786. The slave trade still flourished in 1763, when about 150 ships sailed yearly from British ports to Africa with capacity for nearly 40,000 slaves.

There was no well-organized opposition to the slave trade before 1800, although some individuals and ephemeral societies condemned it. The Spanish church saw the importation of Blacks as an opportunity for converting them. The English religionist George Fox, founder of Quakerism (founded in the 1650s), accepted the fact that his followers had bought slaves in Barbados, but he urged kind treatment. The English novelist and political pamphleteer Daniel Defoe later denounced the traffic but seemingly regarded slavery itself as inevitable. The English and Pennsylvania Quakers passed resolutions forbidding their members to engage in the trade, but their wording suggests that some were doing so; in fact, 84 of them were members of the Merchants Trading to Africa.

Those opposing the slave trade often objected on other than humanitarian grounds. Some colonials feared any further growth of the Black percentage of the population. Others, who justified English slave sales to the Spanish colonies because payment was in cash, condemned the same traffic with French islanders, who paid in molasses and thus competed with nearby English sugar planters.

Colonial wars of the first half of the 18th century

From 1689 to 1763 the British and French fought four wars that were mainly European in origin but which determined the colonial situation, in some cases for two centuries. Spain entered all four, first in alliance with England and later in partnership with France, though it played a secondary role.