For more than three centuries, European ships carried millions of enslaved Africans across the Atlantic to work on plantations and in mines in the Americas. It was one of the largest forced migrations in history, and one of its gravest injustices. Its abolition, beginning with Denmark, Britain and the United States in the early 19th century, did not end slavery itself, but it marked a turning point in the long struggle for human freedom. The story was shaped by the resistance of enslaved people, the campaigns of activists and the hard economics of empire, and it had a direct sequel in the lives of millions of Indians.
How the trade worked
By the 1480s, Portuguese ships were already taking enslaved Africans to sugar plantations on Atlantic islands, and after 1500 the trade expanded to the Americas. Over time, Portugal, Britain, France, the Netherlands, Spain and others all took part. Ships carried manufactured goods such as textiles and guns to West and West-Central Africa, where they were exchanged for captives. The captives were then shipped across the Atlantic in the notorious "Middle Passage", and the ships returned to Europe with sugar, tobacco, cotton and other plantation goods.
The scale was immense. The SlaveVoyages database, built by historians from shipping records, estimates that around 12.5 million Africans were forced onto ships between 1501 and 1866, and that about 10.7 million survived the voyage. Other estimates differ somewhat, and many more people died during capture, forced marches to the coast and imprisonment before departure. The National Archives (UK) estimates that Britain alone transported about 3.1 million Africans, of whom about 2.7 million arrived.
Resistance and the campaign for abolition
Enslaved Africans resisted at every stage, through shipboard revolts, escape, sabotage and rebellion. The most dramatic was the uprising in the French colony of Saint-Domingue that began in 1791 and led to the independent nation of Haiti in 1804, the first state founded after a successful revolt by enslaved people.
In Britain, an organised abolition movement emerged in the 1780s. The Society for Effecting the Abolition of the Slave Trade was founded in London in 1787, with Quakers and activists such as Thomas Clarkson and Granville Sharp at its core. Formerly enslaved writers, most famously Olaudah Equiano, whose autobiography appeared in 1789, gave powerful first-hand testimony. Campaigners gathered evidence, organised mass petitions and promoted a boycott of slave-grown sugar, while William Wilberforce led the cause in Parliament for nearly two decades.
The laws that ended the legal trade
Denmark-Norway was the first European state to legislate against the trade, with a 1792 decree that took effect in 1803. In Britain, the Abolition of the Slave Trade Act was passed on 25 March 1807 and made the trade unlawful from 1 May 1807. The United States banned the import of enslaved people from 1 January 1808. Britain's Royal Navy then set up a West Africa Squadron to intercept slave ships, though the illegal trade continued for decades, especially to Brazil and Cuba.
Ending the trade was not the same as ending slavery. Britain's Slavery Abolition Act of 1833 took effect in 1834, but many formerly enslaved people were forced into an "apprenticeship" system until 1838. The British government also paid £20 million in compensation to slave owners, while the enslaved received nothing. Slavery ended in the United States in 1865 and in Brazil in 1888.
Timeline: key moments
- 1480s: Portuguese ships begin carrying enslaved Africans to Atlantic island plantations.
- 1787: The Society for Effecting the Abolition of the Slave Trade is founded in London.
- 1791: The revolution in Saint-Domingue (Haiti) begins.
- 1792: Denmark-Norway decrees an end to its slave trade, effective 1803.
- 1807: Britain passes the Abolition of the Slave Trade Act.
- 1808: The US ban on importing enslaved people takes effect.
- 1834: Britain's Slavery Abolition Act takes effect.
- 1838: The apprenticeship system ends in British colonies.
- 1888: Brazil becomes the last country in the Americas to abolish slavery.
The India connection
Abolition in the British Empire had a direct and lasting impact on India. When slavery ended in Britain's Caribbean and Indian Ocean colonies, plantation owners looked for new sources of cheap labour, and large numbers of Indians were recruited as indentured workers. They signed contracts, often under pressure or misleading promises, to work for several years on sugar estates far from home.
Mauritius led what the British called the "Great Experiment". UNESCO notes that the immigration depot at Aapravasi Ghat in Port Louis, built in 1849, received indentured labourers from India and several other regions, and that Mauritius alone received almost half a million of the more than two million indentured labourers who travelled worldwide under such systems. Indians also went to the Caribbean, Fiji, South Africa and elsewhere, and their descendants form large communities today. Slavery itself was not covered by the 1833 Act in the East India Company's territories; it was addressed separately in India by legislation in 1843.
Why it matters today
- Resistance changes history. The actions of enslaved people themselves, from shipboard revolts to the Haitian Revolution, were central to abolition.
- Public campaigns work. Petitions, boycotts and testimony helped turn public opinion, a model for later human-rights movements.
- Laws are only a start. The illegal trade, apprenticeship and indenture show how exploitation can continue in new forms.
- Legacies endure. Racial inequality, the global African diaspora and Indian communities in Mauritius and the Caribbean all trace back to this history.
- Modern slavery still exists. Forced labour and human trafficking remain serious global problems today.
Frequently asked questions
When was the transatlantic slave trade abolished?
There was no single date. Denmark-Norway's ban took effect in 1803, Britain's Act was passed in 1807 and the US ban took effect in 1808. Illegal trading continued, especially to Brazil and Cuba, until the 1860s.
How many Africans were taken across the Atlantic?
Historians using the SlaveVoyages database estimate that about 12.5 million Africans were embarked and about 10.7 million survived the crossing. Other estimates vary.
How is the end of slavery linked to India?
After slavery ended in British colonies, planters recruited Indians as indentured labourers. Mauritius alone received almost half a million indentured workers, the large majority of them, by most accounts, from India.
