A Short History of the African Slave Trade

Illustration depicting the traffic of enslaved people on the coast of Africa
Chicago History Museum / Getty Images

Although enslavement has been practiced for almost the whole of recorded history, the vast numbers involved in the trade of enslaved Africans or the African slave trade have left a legacy that cannot be ignored.

Enslavement in Africa

Whether enslavement existed within sub-Saharan African Iron Age kingdoms before the arrival of Europeans is hotly contested among African studies scholars. What is certain is that Africans were subjected to several forms of enslavement over the centuries, including a "traditional" form that considered enslaved people to be the property of their enslavers. Both imperial Muslims within the trans-Saharan trade of enslaved people and imperial Christian Europeans through the trans-Atlantic trade of enslaved people were enslavers.

Between 1400 and 1900, close to 20 million individuals were captured from Africa during four sizable and mostly simultaneous operations orchestrated to trade enslaved people: Trans-Saharan, Red Sea (Arab), Indian Ocean, and Trans-Atlantic trade of enslaved people. According to Canadian economic historian Nathan Nunn, by 1800 Africa’s population was half of what it would have been, had these trades of enslaved Africans not occurred. Nunn suggests his estimates based on shipping and census data probably represent about 80% of the total number of people stolen from their homes by various enslavement operations

Four Great Enslaved Person Trading Operations in Africa
Name Dates Number Countries Most Impacted Destination
Trans-Saharan early 7th–1960s >3 million 13 countries: Ethiopia, Mali, Nigeria, Sudan, Chad North Africa
Trans-Atlantic 1500–1850 >12 million 34 countries: Angola, Ghana, Nigeria, the Congo European colonies in the Americas
Indian Ocean 1650–1700 >1 million 15 countries: Tanzania, Mozambique, Madagascar Middle East, India, Indian Ocean Islands
Red Sea 1820–1880 >1.5 million 7 countries: Ethiopia, Sudan, Chad Egypt and Arabian peninsula

Religion and the Enslavement of Africans

Many of the countries that actively enslaved Africans came from states with strong religious underpinnings such as Islam and Christianity. The Qur'an prescribes the following approach to enslavement: free men could not be enslaved, and those faithful to foreign religions could live as protected persons. However, the spread of the Islamic Empire through Africa resulted in a much harsher interpretation of the law, and people from outside the borders of the Islamic Empire were ultimately susceptible to enslavement.

Before the Civil War, Christianity was used to justify the institution of slavery in the American south, with most clergy in the south believing and preaching that enslavement was a progressive system designed by God to affect the Christianization of Africans. The use of religious justifications for enslavement is not confined to Africa by any means.

The Dutch East India Company

Africa wasn't the only continent from which people were captured and enslaved, but its countries suffered the most devastation. In many cases, enslavement appears to have been a direct outgrowth of expansionism. The great maritime explorations driven by companies such as the Dutch East India Company (VOC) were financed for the specific purpose of adding land to European empires. That land required a labor force far beyond the men sent on exploratory ships. People were enslaved by empires to act as servants; to carry out agricultural, mining, and infrastructure labor; to be regularly exploited for sex and submitted to sexual violence; and to assume the role of soldiers, largely regarded as expendable, for various armies.

The Start of the Trans-Atlantic Trade of Enslaved People

When the Portuguese first sailed down the Atlantic African coast in the 1430s, they were interested in one thing: gold. However, by 1500 they had already traded 81,000 enslaved Africans to Europe, nearby Atlantic islands, and to Muslim merchants in Africa.

São Tomé is considered to have been a principal port in the export of enslaved Africans across the Atlantic. This is, however, only part of the story.

The Triangular Trade

For two hundred years, 1440–1640, Portugal had a monopoly on the export of enslaved Africans. It is notable that they were also the last European country to abolish the institution—although, like France, it still continued to force formerly enslaved people to work as contract laborers, which they called libertos or engagés à temps. It is estimated that during the 4 1/2 centuries of the trans-Atlantic trade of enslaved Africans, Portugal was responsible for transporting over 4.5 million enslaved Africans (roughly 40% of the total). During the eighteenth century, however, when trade accounted for the transport of a staggering 6 million enslaved Africans, Britain was the worst transgressor—responsible for almost 2.5 million. (This is a fact that is often forgotten by those who regularly cite Britain's prime role in the abolition of the trade of enslaved people.)

Information on how many enslaved people were shipped from Africa across the Atlantic to the Americas during the sixteenth century can only be estimated as very few records exist for this period. But from the seventeenth century onwards, increasingly accurate records, such as ship manifests, are available.

Enslaved Africans for the Trans-Atlantic trade of enslaved people were initially captured from Senegambia and the Windward Coast. Around 1650, the trade moved to west-central Africa (the Kingdom of the Kongo and neighboring Angola).

South Africa

It is a popular misconception that enslavement in South Africa was mild compared to that in America and the European colonies in the Far East. This is not so, and punishments meted out could be very harsh. From 1680 to 1795 an average of one enslaved person was executed in Cape Town each month and the decaying corpses would be re-hung around town to act as a deterrent to other enslaved people. 

Even after the abolition of the trade of enslaved people in Africa, colonial powers used forced labor—such as in King Leopold's Congo Free State (which was operated as a massive labor camp) or as libertos on the Portuguese plantations of Cape Verde or São Tomé. As recently as the 1910s, about half of the two million enslaved Africans who supported the various powers in World War I was forcibly coerced to do so.

Impact of the Trade of Enslaved People

Historian Nathan Nunn has conducted extensive research on the economic impacts of the massive loss of population during the trade of enslaved people. Prior to 1400, there were several Iron Age kingdoms in Africa that were established and growing. As the trade of enslaved people ramped up, people in those communities needed to protect themselves and began procuring weapons (iron knives, swords, and firearms) from Europeans by trading enslaved people.

People were kidnapped first from other villages and then from their own communities. In many regions, the internal conflict caused by that led to the disintegration of kingdoms and their replacement by warlords who could not or would not establish stable states. The impacts continue to this day, and despite great indigenous strides in resistance and economic innovation, Nunn believes the scars still hinder the economic growth of countries who lost large numbers of populations to enslavement and trade compared to those that did not. 

Selected Sources and Further Reading

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Boddy-Evans, Alistair. "A Short History of the African Slave Trade." ThoughtCo, Aug. 26, 2020, thoughtco.com/african-slavery-101-44535. Boddy-Evans, Alistair. (2020, August 26). A Short History of the African Slave Trade. Retrieved from https://www.thoughtco.com/african-slavery-101-44535 Boddy-Evans, Alistair. "A Short History of the African Slave Trade." ThoughtCo. https://www.thoughtco.com/african-slavery-101-44535 (accessed May 30, 2023).