The abolition (ending) of slavery marked an important moment in world history. In 1800, there were plantations worked by enslaved people stretching across the Americas. Tens of thousands of people were captured each year in Africa and taken to the Americas. Their journey across the Atlantic was so dangerous that many died on the boat. Those who survived faced a life of harsh labor and terrible living conditions. Slavery and the slave trade began to be outlawed in 1803. In this year, Denmark made it illegal for its citizens to participate in the Atlantic slave trade. In 1807-1808, both the United States and Britain outlawed the slave trade. This meant that it was illegal to bring enslaved people into their territory. They kept slavery legal, however. The people who were already enslaved continued to be enslaved, and their descendants were born into slavery.

Independent Haiti became the first country in the Americas to abolish slavery in 1804. Cuba ended slavery in 1886 and Mexico ended it in 1829. The United States would not end slavery until after the Civil War ended in 1865.

Enslaved people were still smuggled illegally into the Americas. In Cuba and Brazil, slavery remained legal until late in the nineteenth century. But the tide had turned against slavery. Slavery would be outlawed in many other regions of the world in the years that followed.

Why did abolition just “happen” in the nineteenth century? What caused some of the biggest slave-owning and slave-trading societies to suddenly become abolitionists? There are at least three important theories to consider.

Theory 1: Free labor and free wages

Britain underwent one of the most dramatic shifts toward abolitionism. Britain had the world’s largest slave-trading industry in the 1790s, but it became the first large country to make the slave trade illegal in 1807. Slavery was later abolished throughout the British Empire, in English-speaking northern U.S. states and parts of Canada. What changed in these regions?

One theory is that ending slavery had economic benefits for the people living there. The emerging middle class included business owners who used paid workers. They saw slavery as unfairly competing with their businesses. Also, they hoped to trade in Africa, either to sell finished goods or to buy African resources. They hoped that the end of the slave trade would make business in Africa more stable and profitable.

These business people were often competing for political power with an upper class of land-owning nobles. These nobles were likely to have slave plantations. Ending slavery would hurt these political rivals and help level the playing field.

Thus, it can be argued that slavery was abolished only when it made economic sense for some people.

Theory 2: Morality

Some have argued that slavery was ended for moral, not economic, reasons. These changing ideas might have been related to Enlightenment thinking. The Enlightenment, which began in the late eighteenth century, promoted individual freedom. This included “free labor,” meaning that people were paid wages for their work rather than enslaved. Enlightenment thinkers debated who was human, and this got people thinking about the morality of slavery. But, there were limits to this. In general, the new morality did not see enslaved black people as equals.

Slavery had often been defended using Old Testament texts that seemed to justify enslavement. The Enlightenment caused people to question religious authority and interpret Biblical texts themselves. Most abolitionist leaders were evangelical Christians who reread these texts. They noted that the gospel called for “goodwill towards all men.” They argued that slavery went against the spirit of Christianity.

Many of these same abolitionists were also business people who had economic reasons to support abolitionism. However, many were working-class people with no economic reasons to want to end slavery. They were motivated by the belief that the slave trade was evil and immoral. They protested slavery by refusing to buy products produced by enslaved people, such as sugar and rum. These working-class people had little reason to boycott these products other than for moral reasons.

Theory 3: The actions of Africans in the Americas and Europe

There is another theory that looks at black Americans and Europeans. It argues that it was the actions of these people that led to the end of slavery. Many of these people were formerly enslaved or the descendants of enslaved people.

In Britain, some of the most effective abolitionists were black. One example was Olaudah Equiano, a formerly enslaved man who argued that that slavery conflicted with Christian belief. Another free African, Ottobah Cugoano, also played an important role and called for the abolition of slavery in his autobiography.

Black abolitionists played an even larger role in France and its empire. During the French Revolution, black Frenchmen and Frenchwomen, such as Jeanne Odo, called for an end to slavery. The most significant action was the Haitian Revolution. It occurred in the Caribbean colony of Saint-Domingue (now called Haiti), which was France’s largest slave colony. Enslaved people rebelled against the French colonists, fought the French army, and gained their freedom in 1804. They forcibly ended slavery in Haiti and pushed France to end slavery elsewhere. France would abolish slavery in all its colonies by 1848.

In Mexico in the 1820s, abolitionism was also led by people of African descent. Abolition was eventually declared for almost all of Mexico in 1829, by Vicente Guerrero, a president of partly African ancestry.

Conclusion

Most of the world’s nation-states abolished slavery by the beginning of the twentieth century. This does not mean that slavery was fully ended. (It continues to exist in some forms even to this day.) In some places, such as the Islamic World, slavery continued to operate outside of the law. In other places, people were freed but forced to live in conditions similar to slavery. Class systems in South Asia forced people to do harsh work with no real escape. Racist laws in the United States continued to oppress the formerly enslaved. Many freed black people had to work in sharecropping, which was similar to slave labor.