In Britain, America, Portugal and in parts of Europe, opposition developed against the slave trade. Opposition to the trade was led by the Religious Society of Friends (Quakers) and establishment Evangelicals such as William Wilberforce. The movement was joined by many and began to protest against the trade, but they were opposed by the owners of the colonial holdings.


Walter Rodney, a student attending Queen's College in Guyana,  states: "Above all, it was the institution of slavery in the Americas which ultimately conditioned racial attitudes, even when their more immediate derivation was the literature on Africa or contacts within Europe itself. It has been well attested that New World slave - plantation society was the laboratory of modern racism. The owners contempt for and fear of the black slaves was expressed in religious, scientific and philosophical terms, which became the stock attitudes of European and even Africans in subsequent generations. Although there have been contributions to racist philosophy both before and after the slave trade epoch, the historical experience of whites enslaving blacks for four centuries forged the tie between racist and color prejudice, and produced not merely individual racists but a society where racism was so all-pervasive that it not even perceived for what it was. The very concept of human racial variants was never satisfactorily established in biological terms,and the assumptions of scientists and laymen alike were rooted in the perception of a reality in which Europeans had succeeded in reducing Africans to the level of chattel." ... "The role of slavery in promoting racist prejudice and ideology has been carefully studied in certain situations, especially in the U.S.A. The simple fact is that no people can enslave another for four centuries without coming out with a notion of superiority, and when the color and other physical traits of those peoples were quite different it was inevitable that the prejudice should take a racist form."

The Atlantic slave trade arose after trade contacts were first made between the continents of the "Old World" (Europe, Africa, and Asia) and those of the "New World" (North America and South America). For centuries, tidal currents had made ocean travel particularly difficult and risky for the boats that were then available, and as such there had been very little, if any, naval contact between the peoples living in these continents. In the 15th century however, new European developments in seafaring technologies meant that ships were better equipped to deal with the problem of tidal currents, and could begin traversing the Atlantic ocean. Between 1600 and 1800, approximately 300,000 sailors engaged in the slave trade visited West Africa. In doing so, they came into contact with societies living along the west African coast and in the Americas which they had never previously encountered. Historian Pierre Chaunu termed the consequences of European navigation "disenclavement", with it marking an end of isolation for some societies and an increase in inter-societal contact for most others.

However, it was not just along the west African coast, but also in the Americas that Europeans began searching for commercial viability. European Christendom first became aware of the existence of the Americas after they were discovered by an expedition led by Christopher Columbus in 1492. As in Africa however, the indigenous peoples widely resisted European incursions into their territory during the first few centuries of contact, being somewhat effective in doing so. In the Caribbean, Spanish settlers were only able to secure control over the larger islands by allying themselves with certain Native American tribal groups in their conflicts with neighbouring societies. Groups such as the Kulinago of the Lesser Antilles and the Carib and Arawak people of (what is now) Venezuela launched effective counterattacks against Spanish bases in the Caribbean, with native-built boats, which were smaller and better suited to the seas around the islands, achieving success on a number of cases at defeating the Spanish ships.

In the 15th and 16th centuries, colonists from Europe also settled on the otherwise uninhabited islands of the Atlantic such as Madeira and the Azores, where with no slaves to sell, exporting products for export became the main industry. Africans themselves played a role in the slave trade, by selling their captive or prisoners of war to European buyers. Selling captives or prisoners was common practice among Africans and Arabs during that era, just as it had been in ancient Europe. The prisoners and captives who were sold were usually from neighboring or enemy ethnic groups. 

The first Africans imported to the English colonies were also called “indentured servants” or “apprentices for life”. By the middle of the seventeenth century, they and their offspring were legally the property of their owners. As property, they were merchandise or units of labor, and were sold at markets with other goods and services.

The Portuguese were the first to engage in the New World slave trade, and others soon followed. Slaves were considered cargo by the ship owners, to be transported to the Americas as quickly and cheaply as possible, there to be sold to labor in coffee, tobacco, cocoa, cotton and sugar plantations, gold and silver mines, rice fields, construction industry, cutting timber for ships, and as house servants.

The Trans-Atlantic Slave Trade was the most abominable and cruel from of slavery, but it was neither the first nor the only slave trade. Slavery was a recognized institution around the world long before the Egyptians enslaved the Jews. Arabs raided European countries and captured white slaves which they sold in Africa. By the 18th century, a large part of the European population were descendants of serfs and slaves. In other words, slavery was not just about the black people who endured the Middle Passage. It was a part of human history.Worldwide, domestic slavery was the most common form of enslavement. Rich men had slaves in their households, and, in some societies, the number of slaves determined his social status. In West Africa, severe forms of slavery existed. The slaves were usually men and women captured in war whose labor led to surplus production and whose numbers amplified the armies of imperial expansion. In most parts, slaves born within the master's household were better treated than war captives or trade slaves--often as members of the family. Slaves could occasionally rise to positions of importance or buy their own freedom. Nonetheless, a master had ultimate power over his slave.

Slavery was practiced in some parts of Africa, Europe, Asia, and the Americas before the beginning of the Atlantic slave trade. There is evidence that enslaved people from some African states were exported to other states in Africa, Europe and Asia prior to the European colonization of the Americas. The African slave trade provided a large number of slaves to Europeans.

The Atlantic slave trade was not the only slave trade from Africa, although it was the largest in volume and intensity. "The African continent was bled of its human resources via all possible routes. Across the Sahara, through the Red Sea, from the Indian Ocean ports and across the Atlantic. At least ten centuries of slavery for the benefit of the Muslim countries (from the ninth to the nineteenth).... Four million enslaved people exported via the Red Sea, another four million through the Swahili ports of the Indian Ocean, perhaps as many as nine million along the Trans-Saharan caravan route, and eleven to twenty million (depending on the author) across the Atlantic Ocean."

According to John K. Thornton, Europeans usually bought enslaved people who were captured in endemic warfare between African states. There were also Africans who had made a business out of capturing Africans from neighboring ethnic groups or war captives and selling them. People living around the Niger River were transported from these markets to the coast and sold at European trading ports in exchange for muskets (matchlock between 1540–1606 but flintlock from then on) and manufactured goods such as cloth or alcohol.

The Atlantic slave trade or transatlantic slave trade took place across the Atlantic Ocean from the 16th through to the 19th centuries. The vast majority of slaves transported to the New World were Africans from the central and western parts of the continent, sold by Africans to European slave traders who then transported them to North and South America. The numbers were so great that Africans who came by way of the slave trade became the most numerous Old-World immigrants in both North and South America before the late eighteenth century. The South Atlantic economic system centered on making goods and clothing to sell in Europe and increasing the numbers of African slaves brought to the New World. This was crucial to those European countries which, in the late seventeenth and eighteenth centuries, were vying with each other to create overseas empires