The Atlantic slave trade or transatlantic slave trade involved the transportation by slave traders of enslaved African people to the Americas. This trade was operated by slave ships from both Europe and the New World. Some voyages used the triangular trade route and its Middle Passage, particularly in the early phases. Europeans established a coastal slave trade in the 15th century, and trade to the Americas began in the 16th century, lasting through the 19th century. Most transported in the transatlantic trade were from Central and West Africa. In contrast to other slave trades, those taking slaves from Africa generally bought their cargo from West and Central African slave merchants. This applied to Europeans in the transatlantic trade and Arab slave traders supplying their own markets. While Europeans were involved in some raiding, this was uncommon and discouraged. The Portuguese built barracoons in their African slaving bases to gather newly purchased captives ready for the next ship to arrive. Northern Europeans operated some forts as African bases, originally for trading in gold, but later for slaves. However, the usual approach of North European slave traders was to use their ship as a base in which to gather their cargo. This meant these ships spent much longer on the African coast than Portuguese vessels, and the first slaves the slavers bought endured longer confinement on board.
The Americas had, after Australia, a much lower population density than other inhabited continents. Exploitation by the European conquerors of these lands needed a workforce, but the sparse indigenous population was shrinking due to European diseases. Demand for labour could not be met by Europeans, who were reluctant to emigrate at this early stage. The solution was the same used for the sugar plantations of Madeira and Canary Islands : slaves brought from Africa. Slaves were sold in the Americas to work on coffee, tobacco, cocoa, sugar, and cotton plantations, gold and silver mines, rice fields, the construction industry, cutting timber for ships, as skilled labour, and as domestic servants. The first enslaved Africans sent to the English colonies were classified as indentured servants, with legal standing similar to contract-based workers from Britain and Ireland. By the middle of the 17th century, slavery had hardened as a racial caste, with African slaves and their future offspring legally the property of their owners, as children born to slave mothers were also slaves (partus sequitur ventrem). As property, the people were considered merchandise or units of labour, and sold at markets with other goods and services, their prices determined by their health and expected productivity.
The major Atlantic slave trading nations, in order of trade volume, were Portugal, Britain, Spain, France, the Netherlands, the United States, and Denmark. The largest slave trading ports were in South America, with New World-based ships probably carrying more enslaved people from Africa than those travelling in ships with a home port in Europe. The current estimate is that about 12.75 million Africans were loaded onto slave ships for transportation to the Americas. Of these, up to 2 million died during the voyage. About 8 million Africans were enslaved and remained on the African continent. Near the beginning of the 19th century, various governments acted to ban the trade, although illegal smuggling still occurred.
Background
Atlantic travel
The Atlantic slave trade developed after trade contacts were established between the "Old World" (Afro-Eurasia) and "New World" (the Americas). The ocean currents and prevailing winds of the Atlantic represented a barrier to return travel for seafarers who did not understand their pattern, whilst those with sufficient knowledge could use them as a tool to assist them. In the 15th century, European developments in seafaring technologies produced multi-masted sailing vessels with centre-line rudders, replacing the medieval cog and the Mediterranean round ship. This led to vessels more suited to Atlantic seafaring. Between 1600 and 1800, approximately 300,000 sailors engaged in the slave trade visited West Africa. In doing so, they came into contact with societies along the West African coast and in the Americas which they had never previously encountered. Pierre Chaunu termed the consequences of European navigation désenclavement, with it marking an end of isolation for some societies and an increase in inter-societal contact in maritime regions.
Historian John Thornton noted, "technical and geographical factors combined to make Europeans the most likely people to explore the Atlantic and develop its commerce". He identified these as being the drive to find profitable commercial opportunities outside Europe. There was the desire to create an alternative trade network to that controlled by the Muslim Ottoman Empire, which was viewed as a commercial, political and religious threat to European Christendom. European traders wanted to trade for gold, which could be found in West Africa, and find a maritime route to "the Indies" (India), where they could trade luxury goods such as spices, without having to obtain them from Islamic traders.
European overseas expansion led to contact between the Old and New Worlds, producing the Columbian exchange named after Christopher Columbus. It started the global silver trade from the 16th to 18th centuries, and involved the transfer of goods unique to one hemisphere to the other. Europeans brought cattle, horses, pigs, sheep, and chickens to the New World, and from the New World Europeans received turkeys, tobacco, potatoes, tomatoes, and maize. Other commodities becoming important in trade were the sugarcane, coffee, and cotton crops of the Americas, along with their gold and silver.
During the first wave of European colonization, although many Atlantic naval explorations were led by the Iberian conquistadors, members of many European nationalities were involved, including from Spain, Portugal, France, England, the Italian states, and the Netherlands. This diversity led Thornton to describe the "exploration of the Atlantic" as "a truly international exercise, even if many of the dramatic discoveries were made under the sponsorship of the Iberian monarchs". That gave rise to the myth that "the Iberians were the sole leaders of the exploration".
European slavery in Portugal and Spain
Slavery had existed in Portugal and Spain throughout recorded history. The Roman Empire had established its system of slavery in ancient times. Benjamin Isaac posits a proto-racism that existed among Greco-Roman people, referring to Aristotle's statement in his Politics that "slaves are subhuman or lesser men while masters are superior", to justify the inferior status of slaves. Since the fall of the Western Roman Empire, systems of slavery continued in the successor Islamic and Christian kingdoms of the Iberian Peninsula through the early modern era of the Atlantic slave trade. Arlindo Caldeira writes that in 1444, six caravels belonging to a consortium of seamen and merchants docked in Lagos with a cargo of 235 enslaved men, women, and children who had been captured in the Bay of Arguin in what is today Mauritania. These were mostly Muslim Berbers, but also, for the first time, included black-skinned people, likely from sub-Saharan Africa, who had been brought to North Africa over the Trans-Saharan caravan routes. Caldeira says "historians recognized this episode as the beginning of the Atlantic slave trade", although ships in Prince Henry the Navigator's fleet had been bringing enslaved persons from West Africa since 1441. The Portuguese established their first trading post as early as 1448 at Arguin, and in 1455 built a fortress to defend the Portuguese merchants settled there.
In the Middle Ages, religion and not race was a determining factor for who was considered to be a legitimate target of slavery. While Christians did not enslave Christians and Muslims did not enslave Muslims, both allowed the enslavement of people they regarded as heretics or insufficient in their religion. This allowed Catholic Christians to enslave Orthodox Christians, and Sunni Muslims to enslave Shia Muslims. Christians and Muslims approved of enslaving pagans, who came to be a preferred and comparatively profitable target of the slave trade, though on a much smaller scale than the trade in sub-Saharan Black African slaves. White slavery was notable throughout the 14th and 15th centuries, and white slaves were one of the largest slave populations. The slaves sold in Spain during medieval times came from the Black Sea area and the Balkans via the Balkan slave trade and the Black Sea slave trade.
In the 15th century, the Balkan slave trade was taken over by the Ottoman Empire, and the Black Sea slave trade, supplanted by the Crimean slave trade, was closed off from Europe. Spain and Portugal replaced this source of slaves by importing slaves from the conquered Canary Islands and then from mainland Africa. The mainland trade was initially from Arab slave traders, via the Trans-Saharan slave trade from Libya, and then from the African West coast through Portuguese outposts, which developed into the Atlantic slave trade and expanded after the establishment of plantations in the Americas.
By this time, Europeans were using both race and religion as a justification to purchase enslaved sub-Saharan Africans. An increase of enslaved African people from Senegal occurred in the Iberian Peninsula in the 15th century. As the number of Senegalese slaves grew larger, Europeans developed terminologies that associated slavery with skin color. The largest numbers of enslaved Africans were held in Andalusian towns, especially Seville. Colin A. Palmer says, "In 1479 the Spaniards signed the Treaty of Alcáçovas with the Portuguese, granting traders in that country the right to supply Spaniards with enslaved Africans."
Europeans enslaved Muslims and people practicing other religions as a justification to Christianise them. In 1452, Pope Nicholas V issued the papal bull Dum Diversas which gave the King of Portugal the right to enslave non-Christians in perpetual slavery. Thomas says "[t]his clause was obviously intended to include the natives of West Africa." In 1454, Pope Nicholas issued Romanus Pontifex, which laid the foundation for doctrines supportive of empire building.
According to Thomas, conversos, former Jews who had been forcibly converted to Christianity, financed much of the slave trade in Lisbon during the 16th and 17th centuries. He writes that one can speculate how far Muslim mullah-merchants controlled the medieval trade in Black Africans across the Sahara before Portuguese ships were seen in West Africa. In New Spain, Spaniards applied the concept of limpieza de sangre (blood purity) to Africans and Native Americans. Believing their ancestries to be impure even though they might be "New Christians", the Spaniards created a racial caste system, with Black blood more often considered a blemish on a person's lineage.
Ellen Yvonne Simms cites Morner's proposition of three main types of social stratification in colonial New Spain: a caste system, in which membership was set by birth, the estate system, a hierarchy in which rank was determined by customs and laws, and a class system based mainly on economic disparity which allowed upward social mobility. According to Simms, their racist ideology allowed the Spaniards to build a society in colonial New Spain based on racial distinctions, with a white Spanish elite minority controlling all its social, economic, and political aspects, and dominating a large indigenous population alongside the numerous enslaved Blacks who remained at the bottom of the social hierarchy.
African slavery