Chapter 26: Ending the Slave Trade

The practice of slavery was as old as the written word. But in the age of Europe’s global empires, it took a racist and even more sinister turn. Then, in the years between 1807 and 1819, with the rise of liberalism and industrialization, western powers began to end the transatlantic slave trade as a first step to ending slavery. In this episode, we’ll discuss how it happened in France, Great Britain, and the United States.

Sources for this episode include:

Beckert, Sven. Empire of Cotton: A Global History. Vintage. 2014.

“CHRONOLOGY-Who banned slavery when?” Reuters. 22 March 2007. https://www.reuters.com/article/uk-slavery-idUSL1561464920070322

Drescher, Seymour. Abolition: A History of Slavery and Antislavery. Cambridge University Press. 2009.

Locke, John. “Two Treatises of Government.” The Works of John Locke, Volume V. Tegg et al. 1823.

“The Cayenne Experiments.” Lafayette and Slavery: Special Collections & College Archives. 2019. https://sites.lafayette.edu/slavery/the-cayenne-experiments/

Full Transcript

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Let’s pick back up from that conversation we had about slavery in Chapter 3. Slavery had existed for a very long time – thousands and thousands of years. With the rise of monotheism, it became more limited, as people didn’t believe they could own other people who shared their religion. It was replaced by a less egregious form of indenturement called serfdom, but that too started to die down after the Black Death.

Then, starting around 1450 and for the next 400 years, slavery ratcheted up and became more race-based. West African slaves could survive the tropical climate of the Caribbean much better than indentured European could. Reliable trade contacts and networks were established between European colonizers, merchant vessels on the high seas, and African slavers on the continent’s west coast, regularly supplying the Europeans with thousands of newly-captured people for sale.

Those Europeans who did not use slave labor soon found themselves at a disadvantage compared to their economic rivals who did use it. So, until governments were to intervene, slavery would only become more common and more cruel.

But that was a tough sell to European governments. With the huge influx of silver from the New World mines, and ample arable land there, and the native peoples of that New World decimated by disease, chattel slavery made the plantation system Europe’s economic success story. In the late 17th Century, Europeans transported roughly 30,000 Africans to their New World plantations every year. By the late 18th Century, it was more like 75,000 per year.

Never before had slavery been so productive, nor was it expanded so rapidly as it was between 1450 and 1750. And by 1750, European colonies across the world were demographically dominated by slaves, to a degree unprecedented anywhere on earth. And also by 1750 (in large part because of the increasingly liberal-humanist outlooks of the hegemonic French and British) the concept of slavery had become entirely interwoven with racism. It was wrong to own human beings, but as many Europeans chose to see it, Blacks were not really human beings.

Then came the backlash, not only to race-based slavery, but to all slavery. Over the course of the 19th Century, it was almost entirely eliminated across the globe. By the time the Nazis and various Communist regimes were using forced labor in the mid-20th Century, Westerners had come to view it a crime against humanity. And a practice that had existed for as long as the written word was made universally illegal.

But the abolition of slavery did not happen overnight. It was a gradual process in many countries across the world. And before abolition, many countries decided first to tackle the slave trade.

Here’s how it happened…


This is the Industrial Revolutions

Chapter 26: Ending the Slave Trade


Alright, I have a quick correction from last week. @Rational_Gene tweeted me to correct my pronunciation of Count Francesco Zambeccari – I was pronouncing it “Zam-be-CHAR-I” – sorry about that. He also mentions that the first hot air balloon flight in Italy was made by a young aristocrat named Count Paolo Andreani near Milan in March 1784. I didn’t really go into this in Chapter 25, but the Italians were probably only second to the French in terms of enthusiasm for hot air balloons.

Anyway, thank you @Rational_Gene.

Among the things that set France and Britain apart from the countries of the Iberian Peninsula, the Italian Peninsula, and Eastern Europe was the fact that there were no Muslims in their neighborhood. At least not in the 15th or 16th or 17th Centuries. And, therefore, there was no basis for them to own slaves in France or Britain.

And during those centuries, the French and British started building concepts of liberty. Certainly, they were a bit stronger in Britain than in France – but in both cases, it was considered a given that slavery just didn’t exist within their realms. As the Enlightenment picked up, this “freedom principle” became engrained in law. Jurists generally held that, all persons in their jurisdictions were, by right, free. However, beyond their “free soil” and “free air”, they still recognized slavery as a legal practice.

The French and British came to the empire game a little later than the Spanish and Portuguese, who by that point had made slavery a key element of New World imperialism. To catch up, the French and British adopted slavery in their colonies too.

Whether or not they could adopt slavery was a bit of a legal grey area. In Britain, common law forbade hereditary indentured servitude, now that serfdom was gone. Only by first freely entering a contract of limited duration could you become something like a slave. But in the colonies, where Parliament was effectively inconsequential, the local colonists could write their own rules. And generally, they decided that Africans who entered the colony were automatically subject to a life of indenturement that would be passed on to their children. And the British government, like the French, made a point of it to turn a blind eye.

Racism played a big part in this, of course. In Chapter 3 I mentioned the legend of the Curse of Cham, which supposedly gave a Biblical justification for enslaving dark-skinned Africans. There was also a longstanding rumor, first promulgated by North African Muslims hundreds of years earlier, that black West Africans were more servile than others by their nature.

By the 17th Century, this racism had become inseparable from European ideas about slavery. In his Two Treatises, the Father of Liberalism, John Locke, writes “Slavery is so vile and miserable an estate of man, and so directly opposite to the generous temper and courage of our nation; that it is hardly to be conceived that an Englishman much less a gentleman, should plead for it.” At the same time, the Treatise is so protective of man’s right to property, Locke also points to the legitimacy of a planter in the West Indies to have power “over servants born in his house, and bought with his money”.

As anyone who’s ever read about the Milgram experiments or the Stanford Prison Experiment knows, that power often comes with cruelty. And the cruelty forced onto black slaves in the New World was virtually unparalleled in the long history of slavery. Humiliation, rape, and even torture were fairly common. The major reason why the slave trade kept growing and growing was the high mortality rate among slaves on the dangerous Caribbean sugar plantations.

But there was also resistance. Revolts on slave ships were fairly common, and it has been estimated that they may have reduced the size of the would-have-been enslaved population by one million. Religious denominations also began questioning the morality of slavery, especially nonconformist Protestant denominations, especially the Quakers.

Abolitionism was on the rise. In 1777, the first legislative act formally abolishing slavery in an independent, sovereign country was passed in…wait for it… Vermont! Yes, they were not yet part of the American union. But others would follow, including France.


France had a complicated view of slavery in its colonies. Officially, France did not allow slavery. With serfdom fading away, the concept of slavery became somewhat taboo there. And by the 18th Century, anyone on French soil was considered automatically free. Of course, that would be a problem for slavers transporting slaves through France. So, French bureaucrats would classify them as “noirs” or “people in service” rather than “slaves.”

And slavers got away with the ambiguity. Several times a Black slave would reach French soil and then sue for freedom. But the courts were unwilling to acknowledge their freedom as a matter of practicality. Similarly, French Enlightenment thinkers were decisively of the opinion that slavery was morally dubious, but French economists were not as convinced (as, say, Adam Smith was) that slavery was less productive than free labor.

Nowhere else did France have a more valuable enslaved workforce than in the sugar-cultivating colony of Saint-Domingue – what is now Haiti. By 1790, half a million slaves were working on some 8,000 plantations there. 40% of French imports came from Saint-Domingue.

Some abolitionists were organizing in France beforehand – the Society of Friends of the Blacks comes to mind. Limited by the pro-slavery monarchy, they simply published a journal of news from Britain’s abolitionist movement, helping spread those ideas in France. Among those who joined the society was a character who has only received passing mention so far in this podcast: Marie-Joseph Paul Yves Roch Gilbert du Motier, the Marquis de Lafayette.

Born in 1757, Gilbert du Motier was the only son of the previous Marquis de La Fayette, who died in battle during the Seven Years War. Inheriting his father’s title, the 2-year-old Marquis de Lafayette was raised by his grandmother, who taught him the ideals of military glory. At age 15 he was commissioned as an army officer and two years later he was married.

The moment that really sprung him into the history books came in 1776, when, at 19 years old, he learned that Louis XVI was allowing French officers to go to the British colonies in North America, to help the colonists fight for independence.

As an Enlightenment liberal, Lafayette romanticized the idea of liberty and the glory that would come from securing it through military leadership. Paying his own way there and insisting on no pay for his service, he left for America and joined George Washington’s army. Despite having no significant military experience, Washington made him a key general of the revolution.

After helping secure ultimate victory for the Americans at the Battle of Yorktown, Lafayette returned to France. There he joined the Society of Friends of the Blacks and, in 1785, purchased land in the French colony of Cayenne on the South American continent. (What is today French Guiana.) Now, that territory is sort of notorious in French history. Yellow fever and malaria were so prevalent there, that a European sent to French Guiana was effectively receiving a death sentence. But Lafayette wasn’t purchasing it for the white man. With the purchase came 70 slaves, who Lafayette freed and hired as paid laborers. He prohibited any of them from being sold or unduly punished and set up a school to educate their children. He wanted to prove that this free plantation could out-compete slave plantations.

But he had to hand over the day-to-day affairs of the South American plantation to his wife, because then came the French Revolution.

When the Estates-General asked the local communities across the country to submit petitions regarding topics they should address, the Society of Friends of the Blacks made their big move, getting the issue of slavery inserted in nearly 50 of the 600 petitions. (Albeit, in those petitions, slavery ranked way, way lower than most of the other big issues of the day.) Then one of the King’s key advisers, Jacques Necker, made reference to the plight of black slaves in a speech, and the King himself noted the issue needed to be addressed.

At first, the pro-slavery lobby in Paris – made up of Caribbean colonists – managed to defeat virtually every anti-slavery proposal taken up by the Estates General. But as colonists, they were in an awkward position, advocating both for their rights and liberties as French citizens in the New World and for the continued bondage of the Black people they exploited for labor. But if they were to be represented politically in France, would that representation be apportioned for all people in the colonies? Or just free people? Or just white people?

This would become an important question after July 1789, when Lafayette presented his masterpiece to the new National Assembly – The Declaration of the Rights of Man and of the Citizen.

Written with his friend, Thomas Jefferson, the document made no explicit mention of the practice of slavery. But with its first article reading “Men are born and remain free and equal in rights.” …yeah, it’s a little hard to justify slavery then. The declaration was adopted as the preamble to the coming French Constitution, effectively making its contents the supreme law of the land – the significance of which would reverberate across the French Empire and the world.

Yet on March 8th, 1790, the National Assembly decreed that the revolution would not interfere with the “local customs” of French colonies, that overseas slaves were the secure property of their masters, and that the transatlantic slave trade would continue, business as usual.

But later that year, when a free man of color in Saint-Domingue was denied the right to vote, which he believed the Rights of Man did in fact cover, that free man of color led a small insurrection. He was eventually captured and executed, but the ordeal had primed the pump for another insurrection in the colony – a slave revolt.

On the night of August 21st, 1791, thousands of slaves attended a secret voodoo ceremony, went home, and started killing their masters. Within ten days, they controlled nearly the entire northern province of the colony.

The revolt continued into 1792, and the slave army took more and more territory. Fearing it would spread to their colonies, Britain and Spain declared war on France and tried to take over Saint-Domingue. Then, fearing they’d lose the colony altogether if they didn’t bolster the slave army, the French Commissioners in Saint-Domingue – recently sent by the increasingly radical revolutionary government in France – declared slavery abolished across the colony in late 1793.

Not only did the government back in Paris confirm the commissioners’ decision, they went a big step further. On February 4th, 1794, they passed a law abolishing slavery in its entirely, across France and all French colonies. They also promised full citizenship and equal rights for Blacks in the French orbit in the upcoming constitution, although in all the chaos of the French Revolution, that constitution was never adopted.

In the years that followed, the slave army in Saint-Domingue – led by Toussaint Louverture – successfully fought off the British and Spanish. Then they wanted an independent state, with a government of, for, and by the majority black and mixed-race population.

But that was a problem for France’s new empire-minded Consul, Napoleon Bonaparte. In 1802, he sent an expedition to retake the colony. Violence started up again, and within a few months, Louverture was captured and died in prison not long after. But Napoleon wasn’t done. Also in 1802, he re-established slavery and the slave trade.

France became the only country during this period to re-establish its slave trade. Over the next three decades, it would abolish the slavery again, resurrect it again, and finally abolish it again in 1848. The slave trade was finally banned in 1817, by the restored Bourbon monarchy – although it would take many years before the ban was fully implemented. Why? Well, by this point the French recognized that they were far behind the times on this issue. Most other western powers had already outlawed the slave trade by this point, including France’s traditional rival – the British.


Officially, there was no such thing as slavery in Great Britain. The kingdom acknowledged the so-called “Freedom Principle” by which all persons were, by right and birth, free, unless they were justly found guilty of a crime or engaged in a contract of indentured servitude. In practice, this wasn’t always strictly true, at least not with Blacks brought to the island kingdom. But outside the kingdom, in the British colonies, it was the principle of property rights that reigned supreme. To free the slaves would be to rob slaveholders of their property.

In a rather remarkable exchange of views in Parliament, David Hartley MP raised the question of the slave trade – suggesting it was immoral – to which, another MP countered that  “‘some gentlemen may, indeed, object to the slave trade as inhuman and impious,’” but the kingdom’s sugar colonies required cultivation and cultivation required Africans. “Without further imports, the laboring population would decline. Other powers stood ready to meet British needs, as well as their own.” No one challenged these points, not even Hartley, who instead simply urged the Board of Trade to look for ways to reduce the extreme cruelties of the slave trade.

But the inertia wouldn’t last. In the years leading up to the bill, Parliamentary debates had became a daily feature in newspapers across Great Britain. Public buildings began to offer their spaces for public meetings where citizens could discuss the issues of the day. Petitioning and lobbying activities increased. It was a new age of increasing public participation in the political process. And among those who were mobilizing most effectively was the abolitionist movement.

Now, pertinent to us, some historians also credit the Industrial Revolution with the movement to abolish slavery. As Robin Blackburn puts it, the movement happened “‘at a time of exceptional national danger,’ derivative of a ‘radical revival’ and a ‘shakeup within the ruling oligarchy.’” Britons from Adam Smith and John Wesley to Josiah Wedgwood and Joseph Priestly became decisively abolitionist.

Across Great Britain, harvests were better than ever. Industry was booming. Mass production of textiles and iron were increasing material well-being. Despite losing the 13 colonies in North America, the Empire was still growing under the financial stability of war capitalism. In reality, the economic success of Britain was due, in large part, to the availability of cheap goods from slave colonies – cheap sugar, cheap tobacco, and especially cheap cotton. But the British people – particularly the thriving liberal bourgeoisie – were no longer convinced that the empire needed to continue the morally dubious practice of slavery.

The moment the tide turned came in 1787, when the Society for the Effecting the Abolition of the Slave Trade formed in London. Better known as the London Committee, it combined the efforts of disparate abolitionists who had been spinning their wheels in the mud for years. Well-funded by Quaker industrialists and bankers, the London Committee was one of the best organized lobbies in history to that point. It had a sophisticated network for publishing and distributing pamphlets and public reports, creating local meetings, and gathering petitions to send to Parliament.

Among the founding members of the London Committee was Granville Sharp. The son of an Anglican theologian, Sharp had been apprenticed to a linen-maker as a boy. He had an unusually sharp mind and he ended up taking a position as a clerk in the Office of Ordnance. He became a lawyer and a bit of an Enlightenment scholar.

The moment that changed his life came in 1765, when he visited the office of his brother, a surgeon, who was treating a young man named Jonathan Strong. A former slave from Barbados, Strong had been badly beaten by his master, leaving him nearly blind. His sight problems became an impediment to his work, so he was cast out onto the streets, where he became a homeless beggar.

The Sharps decided to help Strong, providing him the medical care he needed, and helping him get a job with a Quaker pharmacist they knew. But then the old master decided he never really stopped owning Strong, and tried to sell him to a plantation in Jamaica. Sharp went to the Lord Mayor to get Strong freed. A legal battle started, and at one point, the slaver challenged Sharp to a duel. Eventually, Sharp managed to win Strong’s freedom, but not without the Court affirming the “property rights” of slave owners.

Sharp was soon approached by other slaves to advocate for their freedom as well. The most famous was the 1772 case of James Somerset, an African native who had been captured and sent to the then-colony of Virginia. He had been taken to England by his master, then escaped. After nearly two months on the run, he was captured. By this point, Sharp had become well read on English law and its concepts of liberty. He briefed Somerset’s lawyers, who advocated – successfully – for his release.

The victory sent shockwaves across the British Empire, as it not only seemed to confirm the humanity of James Somerset, but also the notion that England was “free soil” – and that meant that all those places where slavery was practiced couldn’t really be considered free.

Sharp became more than a legal advocate for slaves. He also became a dedicated proponent of abolishing slavery and the slave trade everywhere, long before that idea was popular. Even as it started gaining popularity, it was soon scrambled by the situation in North America. Because so many Americans had wanted the slave trade to end (and we’ll discuss why later in this episode) the American Revolution actually hampered Sharp’s political efforts, as it lost him key allies for the cause.

But for all the allies he lost across the pond, he found many more among the Religious Society of Friends in his own country. But while the Quakers took the lead with the London Committee’s financing and organization, they needed Sharp to be the visible leader of the movement because, as a civil servant and an Anglican, Sharp would have more clout with Parliament. Together, they didn’t just enlist Quakers and Anglicans, but Unitarians, Congregationalists, Baptists, and Methodists. Religion was the bedrock of the movement because it hit at the blatant immorality of modern slavery.

Some industrialists got on board with abolition. But others – particularly textile manufacturers who depended on access to cheap cotton – resisted. Yet, they could never come close to matching the organized effort of the London Committee, who gathered more than 10,000 names in a petition to Parliament, who took up the issue. While said petitions were dismissed by the government of William Pitt the Younger, bills to abolish the slave trade came up in the House of Commons twelve times over the next eighteen years. Twice they passed in the lower house, before being squashed by the House of Lords. And in those years, the London Committee kept organizing and kept petitioning.

It wasn’t just white men, but black men too. Former slaves like Ottobah Cugoano and Olaudah Equiano became empowered voices for abolition in Britain. Equiano wrote an astonishing memoir about his life as a slave, which opened up British eyes to the horrors of the practice. And it wasn’t just men, but women too, holding “ladies only” meetings where they made public speeches against slavery and drafted petitions. In all, women made up about 10% of the abolitionist petitions, which is pretty striking for the late 18th and early 19th Centuries.

As Britain entered the 19th Century and joined a United Kingdom with Ireland, it began to slow its shipping of slaves from Africa to the Caribbean. Then the Whigs made major gains in the 1802 and 1806 elections, which also saw the introduction of overwhelmingly anti-slavery MPs from Ireland. And as the Whigs took over the reins of government, the London Committee made its next big push.

The Slave Trade Act of 1807 was submitted to the House of Lords in February that year. On February 10th, they approved the bill 100 to 34. On February 23rd, the House of Commons debated the issue. Two days later, at 4-in-the-morning, they voted 283 to 16 to abolish the slave trade. About a month later, the Slave Trade Act of 1807 was approved by the royal accent. The forced transportation of Africans to New World plantations, to live out a life of brutal bondage and forced labor, was made illegal throughout the British Empire.

It was many more years before slavery itself was finally abolished across the empire. But an important move in the direction of liberty had been made. And it wasn’t lost on the members of Parliament that such a vote would be a good slap-in-the-face to their ungrateful former colonies, which professed a love of liberty but were importing slaves at unprecedented rates.

But before the British bill could become law, the former colonies would themselves pass legislation outlawing the slave trade.


The Industrial Revolution may have played a role in the abolition of the slave trade, but as we have seen before, it also played a role in the continuation of slavery well into the 1800s. Cheap cotton fueled industrialization. Still, the Industrial Revolution was taking off at the same time as a new philosophy – liberalism. And with the liberal ideas of the Enlightenment, many countries began making moves in the direction of this most basic liberty.

In 1792, Denmark became the first European country to ban the slave trade in its still-young empire. As the Age of Revolution spread across Latin America, Spain ended the slave trade across its colonies in 1811. Sweden followed in 1813 and the Netherlands in 1814. In 1819, Portugal ended the slave trade at their ports and colonies in the Northern Hemisphere.

And the slave trade was even addressed in the newest modern nation, the United States.

A little background: northern states were more reformed-Protestant and Quaker than the southern states, and in the latter half of the 18th Century, those denominations started turning on the concept of slavery. In the South, meanwhile, white settlers often felt uneasy about the large, enslaved, Black population. Over 60% of the population in South Carolina was enslaved Blacks. The whites were afraid that it could lead to a slave revolt, which would put their lives and property in danger. So, they too favored limiting the importation of additional slaves to North America.

Among the early leaders to ban the slave trade was Anthony Benezet. Born in France in 1713 to a Huguenot family, he had emigrated to Britain at a young age where he became a Quaker before moving to Philadelphia. Almost immediately then he became an outspoken abolitionist and, perhaps more than anyone else, worked to turn opinion against slavery among his fellow Quakers. His writings became influential on both sides of the Atlantic.

Then came the American Revolution. The colonists declared their inherent liberty and equality. The hypocrisy of it did not go unnoticed. As the Tory Enlightenment thinker and man responsible for the dictionary, Samuel Johnson, put it: “American cries for freedom were ‘yelps for liberty’ from ‘drivers of Negroes.’” Other Brits pointed to Thomas Jefferson, in particular, for writing his grand words about rights and freedom in the Declaration of Independence with one hand, while shackling in chains his slaves with the other.

It wasn’t lost on the Americans either. At least not most Americans. And after they achieved their independence and started working on a Constitution, the subject of slavery became a major sticking point.

It could be, in part, because the slave trade had taken a massive hit, due to the Revolution. Between 1778 and 1781, the volume of the British slave trade fell to its lowest point since the 1600s. But it was also, in part, because of growing religious unease about slavery in the northern states. And it could be, in part, because of the heightened spirit of liberty in the air, especially among the Enlightenment thinkers who themselves owned slaves and were uncomfortable about it, like Washington, Jefferson, and Madison.

At the convention, the northern states wanted to end the slave trade, but most delegates from the southern states didn’t want slavery to be subject to federal laws. All international trade, including the slave trade, was supposed to be regulated by the federal government. But slavery itself was to be a state issue. And from the 1780s to the 1820s, every single state north of Maryland abolished the practice. Still, compromise was needed to get the south on board.

So, the delegates inserted this clause into Article I, Section 9 of the Constitution:

The migration or importation of such persons as any of the states now existing shall think proper to admit, shall not be prohibited by the Congress prior to the year one thousand eight hundred and eight, but a tax or duty may be imposed on such importation, not exceeding ten dollars for each person.

By delaying such a law banning the slave trade, the slave trade clause served as one of the many important compromises needed for the constitution’s eventual success in passage and ratification.

Now, by 1803, every state had banned foreign ships from delivering slaves. And so, by 1807, when the British passed their own Act to end the slave trade, Congress also took up the issue. At the behest of now-President Thomas Jefferson, they passed the Act Prohibiting Importation of Slaves. It took effect January 1st, 1808 – the first day allowed by the Constitution. All ships, American or otherwise, were prohibited from bringing Africans to the United States to sell as slaves.

And it was understood that eliminating the slave trade would gradually eliminate slavery, or at least reduce it to something less daunting. By the time of the American Revolution, only about 22% of slaves were actually born on the North American continent. The slave trade was crucial to keeping slavery alive.

AND that meant the new law was not going to be followed all too closely, because the reality of the Industrial Revolution was Britain needed cotton. And soon other European countries needed cotton as industrialization spread to the Continent. And, yes, northern states in the US needed cotton because they were developing textile industries of their own.

With that increasing demand came an increasing demand for slave labor, and so plenty of slavers were still willing to transport Africans to the New World, in spite of the prohibition. It is estimated that 50,000 additional slaves were imported to the US between 1808 and the American Civil War.

Next time, on the Industrial Revolutions, we’re going to turn our attention to what made the Industrial Revolution possible, helped it spread across the globe, improved life on planet earth significantly in many ways, and also made life on planet earth unpredictable, insecure, and often times icky – high finance. See you then.


Don’t forget, I have footnotes available for this episode and all future episodes. You can get them by becoming a supporter on Patreon. Just go to Patreon.com/indrevpod – that’s Patreon.com slash I-N-D – R-E-V – P-O-D – and join at any giving level. Your support helps cover the costs of making this podcast – the books I read for it, the hosting service I use for the MP3 files, and more. Thank you.

Dave Broker