What Was the Transatlantic Slave Trade? KS3 History Guide

The transatlantic slave trade was a system in which European nations, including Britain, forcibly transported millions of enslaved Africans to the Americas between the sixteenth and nineteenth centuries to work on plantations and in mines. It was one of the largest forced migrations in human history. Understanding its causes, operation, and the people who resisted and ended it is a core part of the KS3 history curriculum.

What was the triangular trade?

The transatlantic slave trade operated as part of a broader system of trade that historians often call the triangular trade because it involved three linked journeys across the Atlantic:

Europe to Africa — British and European merchants sailed to the West African coast carrying manufactured goods: textiles, guns, metal goods and alcohol. These were exchanged (often with the involvement of African rulers and merchants) for enslaved people.

Africa to the Americas — the Middle Passage — Ships carried enslaved Africans across the Atlantic to European colonies in the Caribbean, North America and South America. This crossing was known as the Middle Passage.

Americas to Europe — Ships returned to Britain and Europe carrying goods produced by enslaved labour: sugar, tobacco, cotton, coffee and rum. These goods were enormously profitable.

This system operated from roughly the 1550s until Britain abolished the slave trade in 1807 and slavery itself in 1833.

Scale and scope

The scale of the transatlantic slave trade was enormous:

Statistic | Figure
Total enslaved Africans transported | Estimated 12–12.5 million
Number who died during the Middle Passage | Estimated 1.5–2 million
Years the trade operated (broadly) | c.1550–1867
Peak decade of British involvement | 1790s
British ships and voyages (approx.) | Over 12,000 voyages

These figures come from the Trans-Atlantic Slave Trade Database, which holds records of thousands of individual voyages. Britain was one of the largest participants in the trade by the eighteenth century — Bristol, Liverpool and London were all major slaving ports.

The Middle Passage: the crossing to the Americas

The Middle Passage — the transatlantic crossing from Africa to the Americas — was a journey of typically six to twelve weeks, and one of the most brutal episodes in human history. Enslaved people were loaded onto ships in conditions deliberately designed to maximise the number of people carried, not to preserve human dignity or life.

Conditions included:

People chained together in holds with very little space to move or sit upright.

Inadequate food and water.

Exposure to disease, especially dysentery, measles and smallpox, which spread rapidly in the crowded holds.

Extreme heat and poor ventilation below decks.

The mortality rate during the Middle Passage varied but has been estimated at between 10% and 20% of those loaded onto ships — meaning that between one in ten and one in five enslaved people died during the crossing alone. The National Archives holds primary sources including ship records, captain's logs and insurance documents that allow historians to reconstruct individual voyages.

Enslaved people who survived the crossing were sold at auction in the Americas — separated from family members and forced to take names given by their enslavers.

Life under enslavement in the Americas

On arrival, enslaved people were forced to work in conditions of extreme violence and deprivation, primarily on:

Sugar plantations (Caribbean islands, particularly Jamaica, Barbados, Saint-Domingue/Haiti)

Tobacco and cotton plantations (Virginia, the Carolinas, later the Deep South)

Coffee and indigo plantations (Brazil, the Caribbean)

Enslavers used violence and the constant threat of violence — whipping, branding and sale away from family — to maintain control. Enslaved people had no legal rights and were treated as property. Families were routinely separated when individuals were sold.

Who profited from the trade?

The profits from the transatlantic slave trade and from slave-produced goods flowed to a wide range of people in Britain:

Ship owners and merchants in Liverpool, Bristol and London.

Plantation owners in the Caribbean and Americas (many of whom had connections to British aristocracy and Parliament).

Manufacturers who supplied goods traded for enslaved people (including gun-makers, textile factories and metalworkers).

Banks and insurance companies that financed and insured slave-trading voyages.

Historians such as Eric Williams argued (in Capitalism and Slavery, 1944) that profits from slavery helped finance Britain's Industrial Revolution. This is debated among historians, but it is clear that the trade generated enormous wealth for some people in Britain — wealth that was invested in land, manufacturing and infrastructure.

Resistance to enslavement

Enslaved people were never passive victims. Resistance took many forms:

Daily resistance — working slowly, feigning illness, breaking tools, and preserving African cultural practices including music, religion and language.

Escape — running away; in some colonies, groups of formerly enslaved people (called Maroons in Jamaica) established free communities in remote areas and defended them against colonial forces.

Uprisings — enslaved people on ships sometimes led revolts during the Middle Passage. On plantations, revolts and rebellions were a constant fear for enslavers. The most successful was in Saint-Domingue (now Haiti), where an uprising beginning in 1791 led by figures including Toussaint Louverture resulted in the world's first Black republic, established in 1804.

Legal challenges — in 1772, James Somerset, an enslaved man brought to England, successfully argued in the case Somerset v Stewart that slavery was not supported by English law. This case, argued by abolitionist lawyer Granville Sharp, was a landmark in the legal challenge to slavery.

Abolition

The campaign to abolish the slave trade in Britain combined many strands:

Abolitionist campaigners — including Olaudah Equiano (whose published autobiography, The Interesting Narrative of 1789, provided a first-hand account of enslavement and became a bestseller), Granville Sharp, Thomas Clarkson and William Wilberforce.

The Committee for the Abolition of the Slave Trade — founded in 1787 — ran mass petition campaigns, published evidence of the trade's cruelty, and lobbied Parliament.

Enslaved people themselves — whose resistance, uprisings and legal challenges demonstrated that slavery was neither stable nor morally defensible.

Parliament abolished the British slave trade in 1807 (the Slave Trade Act). Slavery itself in British colonies was abolished in 1833 (the Slavery Abolition Act), coming into force on 1 August 1834. Crucially, under the 1833 Act, enslavers — not enslaved people — were compensated by the British government. Enslaved people received nothing; instead, many were required to continue working for their former enslavers for up to six years in a system called "apprenticeship".

At KS3, the key skills are: understanding the scale and causes of the trade, empathising with the experiences of enslaved people while avoiding sensationalism, and being able to discuss who resisted, who profited, and how abolition came about.

The National Archives holds a rich collection of primary sources related to the trade, including ship logs, abolition petitions and the records of the 1833 compensation scheme.

Frequently asked questions

Why did the transatlantic slave trade begin?

The transatlantic slave trade grew from the fifteenth century onwards because European powers — first Portugal and Spain, then Britain, France and the Netherlands — were establishing colonies in the Americas that required large amounts of agricultural labour. Indigenous populations had been devastated by disease and warfare. Enslaved African people were seen as a solution to this labour shortage. The trade was also enormously profitable: the same voyage that delivered enslaved people to the Americas could return with valuable commodities produced by their labour, creating three sources of profit in one circular journey.

What was the Middle Passage?

The Middle Passage was the second of the three legs of the triangular trade — the journey of enslaved Africans from the West African coast across the Atlantic Ocean to the Americas. The crossing typically took between six and twelve weeks. Enslaved people were carried in extremely cramped, inhumane conditions in the holds of ships. Disease was common and mortality rates were high — an estimated 1.5 to 2 million enslaved Africans died during the Middle Passage out of the 12 million transported. The suffering of the Middle Passage was documented by abolitionist Thomas Clarkson, who collected first-hand testimonies from sailors, and by Olaudah Equiano, who described his own crossing.

Who was Olaudah Equiano and why is he important?

Olaudah Equiano (c.1745–1797) was an enslaved African from the Igbo region of what is now Nigeria. He was transported to the Americas as a child, later purchased his own freedom, and in 1789 published The Interesting Narrative of the Life of Olaudah Equiano, or Gustavus Vassa, the African. The book described his experience of enslavement and the Middle Passage in vivid, first-hand detail and became a bestseller in Britain. Equiano was an active member of the abolitionist movement and his autobiography is one of the most important primary sources for understanding the slave trade from the perspective of an enslaved person.

When did Britain abolish the slave trade and slavery?

Britain abolished the slave trade — the buying and selling of enslaved people — in 1807 with the Slave Trade Act. This made it illegal for British ships to carry enslaved people across the Atlantic, but it did not free people already enslaved in British colonies. Slavery itself in British colonies was abolished in 1833 by the Slavery Abolition Act, which came into force on 1 August 1834. Under this Act, £20 million was paid in compensation — but it was paid to the former enslavers, not to the formerly enslaved people. Enslaved people were required to continue working as "apprentices" for up to six years after emancipation.

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