The Atlantic Slave Trade

The Atlantic Slave Trade was one of the most influential, not to say horrific, episodes in world history. It goes without saying that it had an immense impact on Africa, but its effects were far wider. The Americas would today have completely different populations and societies if this trade had not occurred; and the wealth that it brought Europeans almost certainly helped propel them to economic and political dominance over all the other peoples of the world.


1: Backgrounds

The Portuguese Sail to West Africa
Slavery in Africa
European Background

2: The Portuguese Trade System

Expansion along the Coast
Early Impacts on African Societies

3: A New World for Slaves

The Caribbean
The Slave Trade Expands

4: The Atlantic Slave Trade at its Height

To Africa
On the Coast
The Expansion of Supply in Africa
The Middle Passage
The Destination
The Journey Home

5: Impacts

On Europe
The New World

1: Backgrounds

The Portuguese Sail to West Africa

Portuguese sailors began sailing down the coast of Africa in the 1420s. They were trying to find peoples with whom they could trade. For a long time they found nothing but a barren coast, with very few inhabitants. In 1444, however, they rounded Cape Verdi and passed the southern boundary of the Sahara desert. They now found local populations who were eager to trade with them.

The Portuguese had come mainly in search of gold. However, the societies here had a long history of slave trading. The Portuguese began buying human beings from the local rulers.

The Atlantic Slave Trade had begun.

Slavery in Africa

Slavery and slave trading were well established in Africa long before the Portuguese ships arrived off the West African coast. Raiding for slaves was a feature of West African life. It is estimated that between one-third and two-thirds of the population of some West African kingdoms were slaves.

Modern scholars think that the main reason for the prevalence of African slavery was under-population, caused by the many deadly tropical diseases common in this region. This under-population meant that free farmers could move to new, underpopulated areas quite easily. If they wanted to avoid paying taxes to a king, or doing labor service, they could simply move out of his territory.

Because of this, rulers often relied on enslaved people to farm their land and work for them.  Slave raiding and trading was therefore widespread in Africa.

Wars and raids

Wars between kingdoms and chiefdoms, particularly in West Africa, always produced many captives, who were sold in the slave markets right across the region. Many such captives were then sold to merchants for export to North Africa and the Middle East.

The demand for slaves also caused frequent raiding for slaves. Often, such raids were conducted by horse-riding bands from the Savannah kingdoms (just south of the Sahara), southwards into the forest areas. Sometimes such bands would set up a base in the forests, which became the center of a new kingdom – and a new base from which to raid further south.

West African trading network

Gradually a trading network grew up, covering the whole of West Africa. Along this network moved not only slaves, but also gold, salt, ostrich feathers, ivory and other goods. This network also extended northwards across the Sahara desert. These trans-Saharan routes were operated by Muslim merchants from North Africa. They carried thousands of Africans each year to North Africa and the Middle East. (Thousands more were taken up the coast of East Africa to the Middle East – for this, see the Indian Ocean Slave Trade).

Being actively involved in trading was an important part of the role of kings and chiefs. They dealt with long-distance traders in charge of the big trans-Saharan trading caravans. These must have resembled small armies as they travelled along.

By the 15th century, this network of trade routes had spread right to the Atlantic coast. When the Portuguese arrived in their ships, they simply slotted in, dealing with the local chiefs and buying and selling the same goods which the Africans were accustomed to trading in.

European Background

The Portuguese were the first Europeans to undertake long-distance voyages. Portugal was a small southern European kingdom on the Atlantic coast, which had been carved out of Muslim territory. Arab armies had conquered most of this part of Europe in the 8th century AD, and set up several Muslim states here. Then, over the following centuries, the Christians had fought back and reconquered most of their lost territory. Several European kingdoms had appeared, and Portugal was one of these.

In the 15th century, Portugal became the center of a new European activity – organizing long-distance voyages. The aim of these expeditions was to find new lands with which Portuguese merchants could trade. Because of their long coastline along the Atlantic Ocean, the Portuguese were well placed to do this.

They knew that the cities of North Africa traded with peoples south of the huge Sahara Desert. Camel caravans brought valuable goods back from those distant southern lands, of gold, ostrich feathers, ivory – and enslaved human beings.

Under the visionary leadership of a member of their royal family, called Henry “the Navigator”,  from the 1420s the Portuguese set out to probe ever further down the west coast of Africa. Their intention was to open up contact with the peoples who lived south of the desert, to buy gold from them directly rather than in the markets of North Africa.

In the 15th century, millions of Europeans were half-free “serfs”, tied to lands belonging to wealthy landowners. However, full slavery, in which individuals had no rights at all and could be sold from one person to another, was very rare in Europe at this time. There were no slave markets, as there were in the Middle East and Africa.

This changed somewhat in Portugal, with the arrival of slaves from West Africa. These became household servants, or were put to work on the sugar plantations in the south of the country, or in the newly conquered Atlantic island of Madeira.

Sugar plantations

Sugar production had spread westward through the Mediterranean, from the Middle East to Portugal, in the 13th century. The commodity found a strongly expanding market in Europe, where it fetched a high price as a luxury “spice”.

The crop grew on large farms called “plantations”, where gangs of laborers would work together in teams to cultivate the sugar cane, cut it and pulp it in the plantations’ mills. Because the work involved such back-breaking work, sugar plantations in the Middle East had often been worked by slave labor.  Portugal had been one of the few areas in 13th and 14th century Europe where slaves were readily available – from captives taken in the wars with the Muslims in southern Spain. By the 15th century, these wars were mostly over, and the supply of enslaved captives was drying up.

The gaps were filled by enslaved Europeans, often from Eastern Europe (the word “slave” comes from “Slav”, an inhabitant of that region). These had been purchased by Italian and Portuguese merchants from slave markets in the Middle East. However, these slaves became more expensive after the Black Death of the mid-14th century, which resulted in a severe shortage of workers throughout Europe. This was critical in some industries, no more so than in sugar production.

From an early date, Black Africans, purchased from the slave markets of North Africa, had also been used on the sugar plantations. It was a small step for slaves shipped directly in from West Africa to be put to work on the plantations. The opening up of a new source of forced labor from West Africa was a welcome development for the plantation owners.

2: The Portuguese Trade System

One of the main reasons for the Portuguese to explore the West African coast in the first place had been to find gold. Sure enough, the Portuguese found local rulers able and willing to trade gold in exchange for cloth, metals and – slaves. In the years after the Portuguese first arrived in West African waters, therefore, they set up a trading network along the African coast, based primarily on gold, slave and sugar.

This network involved the Portuguese ships sailing from Europe to coastal chiefdoms and kingdoms in West Africa. The region of the Senegal river was the main source of slaves at this time. They were purchased by Portuguese slaving expeditions sailing up the river and buying captives from local rulers along the banks.

Later, the Portuguese bought captives from the king of Benin, and then from chiefs in the Niger Delta region.

From these locations, they shipped the slaves to several destinations. The first was to other African chiefdoms on what later became known as the “Gold Coast”, where the slaves were sold in exchange for gold. To strengthen their control over this valuable trade, the Portuguese leased some land from a local chief and built the first European fort south of the Sahara desert, at El Mina (“The Mine”), in 1482.

Other slaves were taken to sugar plantations which the Portuguese had set up on the islands of Sao Tome, a previously uninhabited island off the coast of Africa which the Portuguese first came across in 1470s. Sao Tome’s tropical climate made it ideal for growing sugar, and the Portuguese set up plantations there almost immediately after discovering it. Here, the Portuguese plantation owners pioneered  the growing and production of sugar in tropical climates, with African slaves.

Slaves were also sent to the sugar plantations on the Atlantic island of Madeira, and a few were shipped back home to Portugal, to work as domestic servants or on the sugar plantations there. Most of the ships returning to Portugal, however, had cargoes of sugar; only a few had slaves on board.

Expansion along the coast

By the early 16th century Sao Tome was the main source of sugar for Europe – by this time Europeans could not get enough of the commodity. To supply slaves for the expanding plantations there, the Portuguese started buying slaves from the Kingdom of Kongo, which they had first visited in 1482. Kongo at this time was a well-organized kingdom which the newcomers treated with great respect. The king accepted baptism in the Catholic Church, and entered into an alliance with his “brother’, the king of Portugal. Soon all the leading men of Kongo were selling slaves to the Portuguese – and raiding their neighbors to get them.

Early Impacts on African Societies

With the rise of the sugar industries in Madeira and then Sao Tome, the number of slaves being taken from certain African societies was growing. Already at this early date it began to cause problems in some places.

In Benin, the king and his advisors came to fear that the slave trade was causing a loss of manpower, and they refused to sell any more adult males to the Portuguese after 1516. In Kongo, the slave trade was soon weakening the stability of the the kingdom, as the nobles took to raiding their neighbors for captives. In 1500, the king of Kongo imposed strict controls over the slave trade.

3: A New World for slaves

In 1492 Christopher Columbus discovered the New World. From the 1520s and 30s onwards , Spanish conquistadores and Portuguese colonists began opening up the Americas to European settlement. This also opened up a huge new market for African slaves.

The Spanish, and later Portuguese, colonists were desperate for a labor force which they could use to mine metals and grow crops in their new possessions. The bulk of the white settlers were not farmers, but soldiers – proud members of the landowning classes in Spain who were entirely unsuited to the back-breaking manual work needed to farm the land themselves. They needed a work force to do this for them.

The Caribbean

Within a generation of Columbus’ expedition, the native peoples of Cuba and Hispaniola had all but vanished, killed off by the diseases the Europeans had brought with them. After 1532,  they found this workforce in black slaves, who they imported in small but steady numbers. Africans had a much greater degree of tolerance to tropical American diseases than Europeans had, and they were accustomed to farming in hot climates. The slaves arrived mostly in Portuguese ships under the “Asiento” system, whereby the Spanish government granted licenses to foreign merchants to ship Spanish cargoes in their holds.

Certain numbers of African slaves also found their way to the gold and silver mines of Peru. However, here the Native American were dragooned into working for their new Spanish rulers. They found themselves farming the land for Spanish landowners and mining for silver in the dreadful conditions of the Spanish- controlled mines. Most of the African slaves remained in the Caribbean region, until the opening up of Brazil.


The Portuguese had established an early foothold in the New World by claiming Brazil in  1500. After several years of neglect, the Portuguese founded sugar plantations in  northern Brazil around 1545. These were at first dependent upon indigenous laborers to work them, but these were soon devastated by disease. After about 1570, there was a wholesale shift to African slave labor.

Northern Brazil proved to be ideal for sugar growing, and the Brazilian sugar industry soon dominated all others, leading to the decline of sugar growing in Portugal, Madeira and Sao Tome.

Soon, the bulk of African slaves arriving in the New World were being landed in Brazil.

The Slave Trade expands

In the years after Christopher Columbus discovered the New World, the Spanish had claimed all the islands of the Caribbean. However, they had not in fact settled many of them. In the 17th century, these fell one by one to the northern European countries of England, France, Holland and Denmark.

These islands remained underdeveloped and of not much economic value for several years. They were home to tiny populations of colonists struggling to make a living.

In 1630, the Dutch, at that time at war with Spain and Portugal, took northern Brazil from the Portuguese. Although they were only there until 1649, when they were ejected, their occupation had long-lasting effects. The Dutch discovered the thriving sugar industry there, and then introduced it to their Caribbean islands. From there, it spread to the English and French islands.

In order to secure supplies of African slaves needed to work the plantations, these countries established bases along the West African coast, from which to trade with the local chiefs. The Dutch took El Mina from the Portuguese in 1637. In the following years the French, British and Dutch built more forts along the “Gold Coast”.

The Northern European Countries

By the middle of the 17th century, countries in northern European such as England and Holland had a larger and more powerful merchant class than those of Spain and Portugal. Both countries had a more democratic system of government than the countries of southern Europe, whose kings were absolutist monarchs.. In Britain, the 17th century was the period when parliament became the most important political institution in the land. In both countries, the merchants had real political influence with their governments.

This meant that the governments of England and Holland actively tried to protect and expand the overseas trade of their countries. Both nations built up powerful navies, and their merchant shipping vastly expanded. In these circumstance, France, as the leading European power, was not to be outdone; her government, although dominated by the king and his court, gave a high priority to expanding her overseas trade and empire.

The Dutch, as we have seen, were the first of these northern Europeans to become systematically engaged in the slave trade. Some English captains, such as the famous Sir John Hawkins, had became involved in the slave trade in the 16th century (as well as piracy against Portuguese and Spanish shipping). However, the regular involvement by British merchants in the trade began in the mid-17th century. In 1660 the Royal Africa Company was founded. It was responsible for establishing trading forts on the Gold Coast, in competition with those of France, Holland and Denmark.

By the late 17th century France had come to own the most valuable of the West Indian sugar islands, above all St Domingue. France’s flourishing slave trade was conducted from its Atlantic ports of Nantes, Bordeaux and Le Havre.

Another country which became involved was Denmark. It came to own a couple of small islands in the West Indies, and leased some land in West Africa from a local chief on the Gold Coast, and built Fort Christianborg on it.

4: The Atlantic Slave Trade at its Height

The 18th century saw the Atlantic slave trade reach its peak. Europeans were growing wealthier during the century, and more people could afford sugar. Indeed, the taste for sweet foods increased greatly at this time. As a result, the market for sugar kept on expanding; after 1750 sugar was the most valuable commodity imported into Europe, outpacing the spices from the East.

Other commodities were also produced in the Americas with slave labor. Brazil came to depend on coffee, while the Caribbean islands produced indigo and molasses besides sugar. In the southern colonies of British North America, tobacco was grown.

However, sugar was by far the most valuable product of the Americas, and it was this which made the Caribbean islands the most highly-prized of all the colonial possession for European powers. In the many wars which were fought between Britain and France, and to a lesser extent Holland, during the 18th century, a major aim was the defense and capture of these islands.

The French and English came to dominated the Atlantic slave trade from the early 18th century. The Dutch, being a smaller nation, had to some extent been squeezed out, though the slave trade remained a large part of its overseas commerce. Denmark always remained a small player.

The Americas also had their own centers of the trade. The Portuguese of Brazil had become deeply involved in the trade during the 17th century, and Brazil remained one of the main centers of the slave trade until its end. It was not only a destination for slaves; it was also a center for the financing and organizing of slaving voyages.

In British North America, the merchants of New York and Boston became active after around 1750.

To Africa

The ships sailing from European ports carried trade goods to be offered to African chiefs and traders in exchange for slaves. These goods were much the same as those sold in the American colonies of the same period: cloth, raw iron and copper, alcohol, tobacco, metal manufactured goods (including firearms), and gun powder.

Slavers had larger crews than most ships of the time, with between 30 and 50 men. On an average slaving voyage, 20 to 30% of the crew could expect to die, mainly from tropical diseases.

The activities of the crew would be similar to those of any other ships until they neared the African coast. Then, the crew would prepare the slave quarters, and the ship would be put on almost a war footing. Preparations were made against attack from Africans of the coast, often in flotillas of sea-going canoes. When successful, they murdered the crews, looted the cargoes and carried off the slaves to sell to other customers.

The danger of attack from the slaves themselves had also to be prepared against. Guns were got up from the hold, mounted and checked. Small arms were brought up to fighting fitness. The gun crews would be trained, and an improvised strong-point and barricades prepared at the center of the main deck. These would allow the crew to mass behind them in the event of a slave rebellion.

Depending on the winds, the voyage from Europe to Africa would normally take between four and nine weeks.

On the coast

Two types of trading systems became established on the West African coast. The earlier one was based on trading forts, where ships took on slaves in bulk. The European forts (which were mostly concentrated along the “Gold Coast” of modern Ghana) were built on land leased from local chiefs, who remained in tight control of the trade with the interior. The gold trade remained the most important activity here until the slave trade overtook it in value about 1700.

From the early 1700s, ships tended to take on slaves by cruising up and down the coast until their holds were full. In most such voyages, more than half of the time – several months – was spent in this way, taking on slaves from the African coast. Sometimes half the crew might be away from the ship at any time, in the boats, exchanging trading cargoes for slaves. This was dangerous work. Boats frequently capsized in the surf, and the trading was often accompanied by violence, both by Europeans and Africans.

Above all, death by disease was very common, especially in West Africa. Sailor after sailor was marked dead in the log books within a few days of the ship arriving off the coast. It was always worst for those who went ashore, and in the rainy season between May and October. The main killers were dysentery (the “bloody flux”), malaria and river blindness.

As the slaves came on board, sometimes one or two at a time, sometimes in small groups, more and more crew had to stay on board to guard them. As the European crew was thinned by disease, the dead seamen were thrown overboard at night, so as not to alert the slaves to the reduced manpower of the crew.

The Expansion of Supply in Africa

As the slave trade grew, new sources of supply were opened up, and soon slaves were being taken from almost the whole west coast of Africa.

West Africa

The increase in demand coincided with turmoil in West Africa.

In what is now Sierra Leone, in the early 18th century, a people called the Mande migrated from the interior and settled in the coastal highlands of. To do so, they had to overcome the resistance of the previous inhabitants, and sold thousands of them as slaves on the coast.

Several kingdoms, their armies, now equipped with firearms, were expanding their borders. In today’s Ghana, the kingdom of Asante, inland from the coast, rose to power in a bloody contest with its rivals. To the east, the West African kingdoms of Oyo and Dahomey were also expanding at this time, swallowing up neighbors.

Such warfare was not only aimed at gaining territory, but at securing control of the slaving routes running through the forests to the coast. This was the case with all three kingdoms mentioned above, Oyo, Dahomey and Asante. This stretch of coast became known to Europeans as the “Slave Coast”.

There seems little doubt that some societies in West Africa were becoming increasingly geared up to meet the demands of the slave trade. The large kingdoms of West Africa had traditionally relied on horse cavalry for  their armies. These were now equipped with guns. Their traditional annual sweeps for captives, long pre-dating the coming of the Atlantic trade, became far more effective. In Senegambia, new kingdoms arose which were structured around armies of mounted, gun-toting slaves, organized primarily for slave raiding.

In the region where the great river Niger reaches the coast in a wide delta, a brand new group of societies appeared, created by the slave trade itself. These were the Aro Confederacy of trading states, whose societies were built around “canoe houses”.  These were family households which had expanded to become large trading companies. They sent fleets of canoes upstream to collect slaves for sale to the Europeans on the coast.

In these ways, hundreds of thousands of war captives became available for sale each year. Such was the scale of this supply that the trade price of these human beings remained very low.

Who were these captives?

Many male slaves who had been freed were interviewed by European missionaries in the early 19th century, and the following picture emerged:

About a third were war captives. This label includes those captured in the great slave raids carried out by the cavalry armies of powerful kings.

Just over a tenth were condemned to slavery for crimes, usually on a charge of adultery. Somewhat fewer were condemned to slavery for debt. Also, many sold themselves into slavery to avoid famine (the slave trade always spiked in famine years).

Many already in slavery to Africans were sold to traders or Europeans by their masters.

Almost two-thirds of all Africans exported were males aged 16 to 40. This contrasts with the slavery within African and Muslim society, where female slaves were favored. Women and children were also captured in raids, but were often kept by their original captors rather than being sold on.

Stateless Societies

One category should be marked out for special attention. Just under a third of captives were kidnapped, often in small-scale raids on villages. People living in independent villages in “stateless” societies were particularly vulnerable.

West Africa had a number of “stateless” societies. In these, the people lived in many independent villages. These villages were very vulnerable to slave raids, and huge numbers of the people who lived in these societies ended up on the slave ships heading for the New World, even though they often resisted capture with great courage and determination.

When captured, they were far more likely to escape or commit suicide than other Africans, or kill their new master, whether African or European. Once in the plantations of the New World, it was slaves from such societies who tended to escape to form the free societies in the forests and mountains, or lead rebellions.

The journey to the coast

In West Africa, the enslavement and transport of people to the coast was entirely in the hands of Africans. It has been estimated that, for every 100 Africans targeted for enslavement in the interior, 10 died while being captured, or as a direct result of capture.

Once enslaved, whether by war or kidnap, captives were either marched in chains to the coast, along long-established trade routes, or thrown into canoes for transport down the river Niger.

In most cases, the captives were now in the hands of large organizations, well used to handling large numbers of slaves. These organizations were often directly controlled by kings and chiefs. They could also be large trading organizations, for example those of the Soninke merchants, who had controlled these routes for centuries. Enslaved people had always been a common item of merchandize for them. The Aro trading houses were also active, with their fleets of canoes, as noted above.

It was imperative to get the newly-captured slaves away from their homelands as soon as possible. The further away they were taken, the less temptation there was to escape. The slaves were taken in forced marches, often over hundreds of miles. The treatment of the traumatized human beings was terrible. It has been estimated that, of 100 Africans targeted in the interior, as many as 22 died on the way to the coast (meaning that, of these 100, on average a third had died before they even reached the Atlantic ocean).

At the coast

Having survived the march to the coast, the slaves were held in pens whilst they waited for a European ship captain sailing up and down the coast to buy them.

The time spent in these coastal slave pens was one of high death rates from disease. Also, many slaves committed suicide. It has been estimated that, of 100 Africans captured in the interior, 10 died in the coastal towns. This, getting on for half of those originally captured had died before setting foot in a European ship.

On the coast, where the slaves were actually sold to the Europeans, the slave trade was mostly in the hands of coastal middlemen, either African (as in the Aro traders, noted above) or of mixed race. In some places along the coast, towns grew up housing a completely new kind of hybrid Afro-European society, entirely geared to the slave trade.

These middlemen strove to protect their position by preventing traders from the interior meeting with the Europeans. They did this partly by telling each that the others were cannibals! (This of course intensified the fears of captives being taken aboard the European ships.)

Central Africa

The Portuguese had been squeezed out of West Africa in the 17th century, so now concentrated their efforts on Central Africa.


By the mid-17th century, provincial chiefs of the kingdom of Kongo, their followers armed with guns, were active as slave raiders and traders. Fighting for control over the trade, they became involved in a brutal civil war. The kingdom of Kongo fell into chaos. Its place was eventually taken by more warlike states such as Ndongo, to a large extent geared to slave raiding.


In Central Africa, the slave trade brought into being specialized war bands, armed with guns, who terrorized the region. They raided inland and sold their captives to the Portuguese on the coast. They competed with slaving caravans setting out from the coast, led by Afro-Portuguese leaders and penetrating deep into the interior.

Traditional societies were destroyed over an expanding region. Refugees streamed eastwards, further into the interior, to escape the slavers. New kingdoms, often formed by war bands, arose. These new kingdoms, armed with guns, took to raiding even further inland.

In the late 18th century, slave raiders from the Atlantic Ocean encountered slave raiders from the Indian Ocean, in the center of the continent. The peoples of this region were now prey to raiders from both directions.


One effect of the slave trade on African societies, especially in central Africa, was the spread of secret societies. The most widespread of these was the Lemba cult.

Lemba was a disease. Some modern scholars think it may have been a state of anxiety. It most affected members of the ruling class of the states of the Congo region.

Sufferers thought it was caused by sorcery, the work of jealous people. They joined together to form Lemba societies, entry to which was very expensive.

These paid for Lemba healers, priests who performed special rituals to ward off curses. However, the society soon came to control markets, acted as police and administered the courts. They therefore became an instrument of control by the wealthy elite over the rest of society.

The Lemba cult eventually crossed the Atlantic to the Caribbean, where it flourished as a strand within Voodooism.

The Middle Passage

The notorious “Middle Passage” is that part of the slaves’ experience which has most stuck in the minds of later Europeans. The slaves were packed tightly together for the duration of the one- or two-month journey, chained and with barely room to move.

It was in the captain’s interest for the slaves to arrive in as good a condition as possible. He was paid by the slave delivered. The slave quarters were scrubbed daily, and the slaves were taken up on deck (weather permitting) for some fresh air and exercise. This sometimes involved whipping them to make them “dance”.

However, it was impossible to maintain healthy conditions on board these small, cramped ships. Accounts by survivors of this ordeal stressed the appalling overcrowding and disgusting atmosphere in the slave quarters. They also referred to the thirst (fresh water was scarce), and the brutality of the European crews.

The Middle Passage killed on average just under 15% of the slaves (and more than 15% of the crew). Mortality rates decreased over time, mainly due to the faster ships used. The voyage time decreased from about 2.5 months to under 2 months.

It has been estimated that, of 100 Africans captured in the interior of Africa, 6 died at sea (the death rate for the the European crew was comparable, perhaps higher). Women and children survived better than men. The bodies of both crew and slaves were dumped overboard at night, and sharks sometimes followed ships for a month.

A minority of voyages (about 5%) experienced a slave mutiny, half of which were successful.

As the ship approached the West Indies or America, the crew prepared the slaves for close inspection by the planters and slave merchants. They washed and oiled all the slaves and shaved the men.

The Destination

On arrival, the slaves were sold at auction. Many slaves died very soon after disembarking. This was either from on-board diseases, New World diseases, or mental trauma. Of 100 people captured in the interior of Africa, three on average died in the Americas before starting work.

Most slaves soon found themselves at work on a  plantation. Many slaves died in the first year from New World diseases. If they survived the first year, they were usually immune.

The Journey Home

The unloading of their human cargo by the crew of a slaving ship often took several weeks. If in the Caribbean, during this period more sailors were liable to die from tropical disease.

With the slaves disembarked, the crew began the last leg of the voyage – the journey home.

For the homeward voyage, the cargo of slaves was often replaced by stone ballast. This was because the trade between Europe and the West Indies was mostly carried out in smaller, faster ships than those of the slavers.

5: Impacts

On Europe

The expansion of demand for Sugar

The Atlantic Slave Trade is often referred to as the “triangular trade”. This is because it was  composed of three legs, which form what looks like a rough triangle on a map of the Atlantic ocean.

In the first leg, manufactured goods were sent to Africa in exchange for enslaved Africans. The second leg involved these Africans being taken to the Americas, where they were exchanged for sugar and other tropical produce. A final leg saw this tropical produce being carried to Europe.

The trade was extremely profitable. It increased the wealth of the northern European countries, already some of the wealthiest societies in the world at that time; and so helped to lay the foundations for the coming of the Industrial Revolution at the end of the 18th century.


This country was the one to benefit most from the Atlantic Slave Trade – which spread far beyond a few trading cities such as Bristol and Liverpool.

Birmingham was where many of the metal goods used in the slave trade were manufactured. For example, it specialized in cheap guns for the African market. Manchester and surrounding areas produced most of the cotton for the trade; and of course London provided much of the financial backing.

The transport links connecting these cities were directly affected. In the later 18th century, canals were dug connecting the inland cities of Birmingham and Manchester with Liverpool and Bristol. Canals also crossed the country from London to the north. The slave trade thus directly helped lay the foundations for the coming Industrial Revolution. The trade’s indirect impact had the same effect. The increased wealth that it brought into the country led to increased demand for manufactured goods, and this encouraged industrialization.

France and Holland

In France and Holland, the profits from the trade helped merchants, bankers, investors and other members of the middle classes to flourish. In France, the increased wealth of the middle classes weakened the power of the old feudal aristocracy. This eventually helped to bring about the French Revolution, which broke out in 1789.  The enslavement of millions of Africans thus ultimately helped to lead to greater freedom for millions of Europeans.

The New World

The Caribbean

The Native American populations of the Caribbean islands had virtually disappeared soon after the Spaniards arrived. As sugar plantations became established in the islands under Dutch, French and British control, the plantation owners at first tried to man them with “indentured servants”. These were poor white workers, often criminals, contracted to serve a master for a few years. There were never enough of these, however, especially as tropical diseases killed Europeans off in great numbers.

Naturally, therefore, the plantations soon came to be manned by African slaves. Given the abundant supply of slaves from Africa, it was less expensive for the plantation owners to replace their slaves with new batches from Africa, rather than encouraging them to breed. Pregnant women and young mothers could not work very hard, and young children were just extra mouths to feed. In any case, the majority of African slaves were male war captives. This meant that the demand for new slaves never slackened.

More and more plantations were established to meet the ever-growing demand for sugar: the 18th century saw the slave trade expand until it reached a peak in the 1780s. By this time most of these small islands housed some of the most unequal societies the world has ever seen. They were inhabited almost completely by enslaved populations of African descent (with a small mixed group of Afro-European make-up, mostly also enslaved, as a small managerial class), over whom a tiny number of European families wielded complete power.

Unsurprisingly, the islands were the setting for occasional slave revolts, though all (until the one in Haiti which freed it from French rule between 1791 and 1804) were unsuccessful. However, slaves frequently succeeded in escaping and forming societies of free Africans in the interior of some Caribbean islands, notably British-ruled Jamaica and Spanish-ruled Cuba, as well as in areas bordering the Caribbean, for example Dutch-ruled Suriname, in South America, and Belize, in central America. In several cases, these societies, protected by inhospitable mountains and forests, were able to defeat European troops sent to bring them under control. In such cases treaties ere signed with the colonial power guaranteeing them freedom within the areas they inhabited.


The majority of all African slaves who arrived in the Americas were taken to Brazil – perhaps 70% of the total. Having been squeezed out of West Africa, the Portuguese took most of these slaves from central Africa.

Sugar remained the main export of Brazil until the 1700s. By then, however, competition from the Caribbean had dented profits, and the sugar industry went into decline. This did nothing to stem the import of slaves. In the south of the country, around Rio de Janeiro, coffee plantations became important in the 18th century. These required large numbers of slaves to work them.

In any case, African slaves – or people descended from them – were by now an important part of the colonial society of the country. The region was acquiring the social and racial mix which would characterize it through much of its history – a small, mostly white ruling class at the top, a large, mostly African laboring class at the bottom, and a small mixed-race class in between.

North America

Black slaves were first brought to Virginia in 1619, and later to the other southern colonies of British North America, but numbers remained small for decades. Most laboring work was done by “indentured” labor – poor white workers contracted to serve a master for a number of years.

In the later 17th century, however, rising wages in England meant that the supply of poor white labor dried up. There was a mass replacement of white workers by African slaves in the 1660s and 1670s. At this period, tobacco was the most usual plant grown.

The slave-worked plantations were always smaller here than in the sugar islands of the Caribbean, and there was also a much larger white population. However, in the 17th and 18th century, the foundations were laid for a society in which slavery played an important part.

After the American Revolution of 1776-83, most of the British colonies became the United States of America. In the 19th century, slavery would bring the southern states into conflict with the northern states. The terrible Civil War of 1861-65 would be the result, ending slavery in the country.


West Africa

The European demand for slaves almost certainly increased warfare within West Africa. The introduction of firearms from Europe made that warfare more destructive.

Eight to ten million enslaved Africans reached the New World between 1500 and 1870. Possibly the same number again died on the way, from disease, suicide and mistreatment (see above). Whereas modern scholars mostly agree that the slave trade did not lead to population decline within West Africa, they believe that it did hinder population growth. It may even have prevented any growth at all from taking place during the 18th century.

Central Africa

The slave trade had a catastrophic impact in the region of modern day Angola and central Africa.

Even before the slave trade, this was a thinly populated region. The taking of millions of people (about a third of the slaves came from here) led to serious population decline. To make matters worse, as populations fled into the interior, they were met by Arab slavers from the Indian Ocean.

Throughout large areas of Central Africa, traditional cultures were debased and brutalized as tribal societies dissolved into armed bands.

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