The slave trade began in America in the 15th century and most of the ships were owned and crewed by Europeans. Those doing the actual kidnapping were often Africans or Arabs.
Another source for large numbers of slaves was prisoners captured in inter tribal conflict or warfare. It was common practice to kill captives, trade them to other tribes, or even sell them at the coast to shippers in the slave trade. Reference material available at:
For the British to end of the slave trade, significant obstacles had to be overcome. In the 18th century, the slave trade was an integral part of the Atlantic economy. The economies of the European colonies in the Caribbean, the American colonies, and Brazil required vast amounts of man power to harvest the bountiful agricultural goods. In 1790 the British West Indies, islands such as Jamaica, Barbados, and Trinidad had a slave population of 524 000, while the French had 643 000 in their West Indian possessions. Other powers such as Spain, the Netherlands, and Denmark had large numbers of slaves as well. Despite these high populations more slaves were always required. Harsh conditions and demographic imbalances left the slave population with well below replacement fertility levels. By 1800 the English had imported around 1.7 million slaves to their West Indian possessions since 1600, the fact that there were well over a million fewer slaves in the British colonies than had been imported to them illustrates the conditions in which they lived.
The immorality of slavery was excused by economics. Slavery was involved in some of the most immensely profitable industries of the time. 70% of the slaves brought to the new world were used to produce sugar, the most labour intensive crop. The rest were employed harvesting coffee, cotton, and tobacco, and in some cases in mining.
These products would be shipped to Europe or Africa. The ships from Europe would then return carrying manufactured materials and foodstuffs. The ships from Africa would return carrying slaves. The entire economy of the Atlantic sector depended on fresh supplies of slaves to the West Indies, and this triangular Atlantic trade formed the core of maritime trade throughout the world. These colonies were some of the most important possessions of each European power.France in 1763, for instance, agreed to lose the entire vast colony of New France in exchange for keeping the minute island of Guadeloupe.
By far the most successful West Indian colonies in 1800 belonged to the United Kingdom. After entering the sugar colony business late, British naval supremacy and control over key islands such as Jamaica, Trinidad, and Barbados gave it an important edge over all competitors. This advantage was reinforced when France lost its most important colony, St. Dominigue, to a slave revolt in 1791.
The British islands produced the most sugar, and quickly the British people became the largest consumers of sugar. West Indian sugar became ubiquitous as an additive to Chinese tea. Products of American slave labour soon permeated every level of British society with tobacco, coffee, and especially sugar all being indispensable elements of daily life for all classes.
To support its colonies Britain also had the largest fleet of slave ships, mostly operating out of Liverpool and Bristol. In Liverpool, by the late 17th century, one out of every four ships that left harbour was a slaver. They were highly profitable ventures and played very important economic roles in those two cities.
How did the abolition of the slave trade occur if it was so economically important and successful? The historiography of answers to this question is a long and interesting one. Before the Second World War the study of the abolition movement was performed primarily by British scholars who believed that the anti-slavery movement was probably among the three or four perfectly virtuous pages in the history of nations.
Williams' thesis was soon brought into question as well, however. Williams based his argument upon the idea that the West Indian colonies were in decline at the early point of 19th century and were losing their political and economic importance to Britain. This decline turned the slave system into an economically burdensome one that the British were only too willing to do away with.
The main difficulty with this argument is that the decline only began to manifest itself after slave trading was banned in 1807 before which slavery was flourishing economically. The decline in the West Indies is more likely to be an effect of the suppression of the slave trade as the cause. The falling prices for the commodities produced by slave labour such as sugar and coffee can be easily discounted as evidence shows the falls in price lead to great increases in demand, actually increasing total profits for the importers. Profits for the slave trade remained at around ten percent of investment and showed no evidence of being on the decline. Land prices in the West Indies, an important tool for analysing the economy of the area did not begin to decrease until after the slave trade was discontinued. The sugar colonies were not in decline at all, in fact they were at the peak of their economic influence in 1807.
Williams also had reason to be biased. He was heavily involved in the movements for independence of the Caribbean colonies and had motive to try to extinguish the idea of such a munificent action by the colonial overlord. A third generation of scholars lead by the likes of Drescher and Anstey have discounted most of Williams arguments, but still acknowledge that morality had to be combined with the forces of politics and economic theory to bring about the end of the slave trade.
The movements that played the greatest role in actually convincing Westminster to outlaw the slave trade were religious. The rising of evangelical protestant groups coupled with the Quakers in viewing slavery as a blight upon humanity. These people were certainly a minority, but they were a fervent one with many dedicated individuals. These groups also had a strong parliamentary presence controlling 35-40 seats at their height, and their numbers were magnified by the precarious position of the government. Known as the "saints" this group was lead by William Wilberforce, the most important of the anti-slave campaigners. These parlimentarians were extremely dedicated and often saw their personal battle against slavery as a divinely ordained crusade.
After the British ended their own slave trade, they were forced by economics to press other nations into placing themselves in the same economic staightjacket, or else the British colonies would become uncompetitive with those of other nations. The British campaign against the slave trade by other nations was an unprecedented foreign policy effort. Denmark, a small player in the international slave trade, and the United States banned the trade during the same period as Great Britain. Other small trading nations that did not have a great deal to give up such as Sweden quickly followed suit, as did the Dutch, who were also by then a minor player.
Four nations objected strongly to surrendering their rights to trade slaves: Spain, Portugal, Brazil (after its independence), and France. Britain used every tool at its disposal to try to induce these nations to follow its lead. Portugal and Spain, which were indebted to Britain after the Napoleonic Wars, slowly agreed to accept large cash payments to first reduce and then eliminate the slave trade. By 1853 the British government had paid Portugal over three million pounds, and Spain over one million in order to end the slave trade. Brazil, however, did not agree to stop trading in slaves until Britain took military action against its coastal areas in and threatened a permanent blockade of the nation's ports in 1852.
For France, the British first tried to impose a solution during the negotiations at the end of the Napoleonic Wars, but Russia and Austria did not agree. The French people and government had deep misgivings about conceding to Britain's demands. Not only did Britain demand that other nations ban the slave trade, but also demanded the right to police the ban. The Royal Navy had to be granted permission to search any suspicious ships and seize any found to be carrying slaves, or equipped for doing so. It is these conditions especially that kept France involved in the slave trade for so long. While France formally agreed to ban the trading of slaves in 1815, they did not allow Britain to police the ban, nor did they do much to enforce it themselves and thus a large black market slave trade continued for many years. While the French people had originally been as opposed to the slave trade as the British it became a matter of national pride and they refused to allow their policies to be dictated to them by the British. Also such a reformist movement was viewed as tainted by the conservative backlash after the revolution. The French slave trade thus did not come to a complete halt until 1848.
See also: Triangular Trade