In order to curtail this piracy, in 1415 the Portuguese invaded and occupied the port of Ceuta, Morocco which guards the southern entrance to the Strait of Gibraltar. This first major conquest by the Portuguese signaled the beginning of an empire building exercise that would span the next 200 years and extend across 4 continents.

By 1425 they had colonized the Madeira Islands off the West coast of Morocco and shortly thereafter began successfully growing sugar cane with the help of African slave labour. This development set a tragic precedent, establishing slave labour as a fundamental component of successful sugar cane plantation agriculture.

As they continued their exploration of the NW coast of Africa the Portuguese found it more and more difficult to return home due to the prevailing North-Easterly Trade Winds. The solution they discovered was to sail in the wrong direction, far out into the Atlantic in order to make their way to a location where they could encounter winds more favourable for their voyage back to Portugal. This manoeuver, called the "Volta do Mar" subsequently played an important if accidental role in the discovery of Portugal's most valuable colony.

In 1500 a large Portuguese fleet under the command of Pedro Álvares Cabral accidentally sailed too far west and ended up being the first Europeans to land in Brazil. This was a singularly important event. By Papal decree, Portugal could claim certain lands in the "New World" East of the discoveries made by Columbus. As a result, this very small European nation gained possession of a huge new territory in Brazil that was ideal for sugar cane production. Having participated in the African slave trade for decades, the obvious solution for the Portuguese was to employ slave labour to work their new plantations. In 1533 the first shipment of African slaves to Brazil initiated what has become known as the Atlantic triangular slave trade.

European goods, notably weapons, were traded to African princes for slaves. The slaves were then transported across the Atlantic and sold, initially to Brazilians, and later to British, Dutch, and French colonists throughout the Caribbean Islands, primarily to work in sugar plantations and in gold and precious jewel mines. Sugar, tobacco, cotton, and coffee were then transported from the "New World" to Europe representing the third leg of the trade route. This pattern of trade turned African slaves into a valuable commodity - so valuable that conflicts between African Kingdoms began to occur for the primary purpose of taking prisoners that could be enslaved.

From 1580 to 1640 the Iberian union of Spain and Portugal resulted in near monopoly in the slave trade for the Portuguese. Cartagena, Veracruz, Buenos Aires, and Hispaniola received the majority of slave arrivals, mainly from Angola. After the breakup of the Iberian Union, Dutch and English slave traders stepped in beginning what is known as the 2nd Atlantic Slave trade.

As the use of African slave labour spread throughout the Carribean planters in the British Colonies took note. In 1619, the first shipment of slaves arrived in Jamestown, Virginia. Over the next two hundred years the transport of slaves by New England vessels became an important component of the fledgling colonial economies.

More than a Century later the political map of North America was about to change forever. At the end of the Seven Year's War in 1763 Britain was in dire financial straits. Seeking to tap into the growing prosperity of its North American colonies in 1769 the British Parliament imposed, for the first time, direct taxation on the American Colonies. Refusing to accept taxation without representation in the British Parliament, the thirteen British colonies declared their Independence in 1776 and formed the United States of America.

By that time there were approximately 460,000 slaves in the new nation, primarily working on plantations in Maryland, Virginia and the Carolinas. New York, because of its long tenure as a Dutch Colony, also had a significant slave population of approximately 19,000.

The widespread use of slave labour was an important and accepted element of the American economy and consequently was recognized explicitly in the United States Constitution adopted in 1789.

1. In terms of determining representation to Congress a compromise position was agreed upon, which counted 3/5 of every slave as a "person".

2. The "Fugitive Slave" clause required that any enslaved person that managed to get to a state where slavery was illegal was not emancipated but instead must be returned to the slave owner. This clause enshrined the concept of chattel slavery whereby the slave was essentially a piece of property rather than a person before the law.

3. The Constitution explicitly prevented Congress from changing the laws with respect to importing slaves until 1808. This provided at least 19 years "grace" to states that were dependent upon the Atlantic Slave trade and to the merchant ship owners that would need to find a different cargo to transport.

The third provision anticipates that the growing abolitionist movement might lead to the banning of slave ships from American ports. Even at this early stage the tension between states dependent upon slave labour and those desirous of ending the ownership of humans was evident.

At this crucial point in the development of the American slave economy a technological innovation radically changed the economics of slave ownership. The invention of the cotton gin in 1793 led to a twenty times increase in the productivity of a person preparing cotton balls for use in clothing manufacture . This, in turn, meant that cotton produced by slave labour could be harvested very profitably and in large quantities - enough to feed the textile mills in the Northern States, Britain, and France that were among the first large enterprises benefitting from the industrial revolution.

While the Southern economy was growing ever more dependent upon slave labour the North was abandoning the practice of slavery altogether. In the 25 years after the Declaration of Independence the seven New England States had essentially become "Free" states. Most of those states did not immediately abolish slavery or free enslaved people. Such a move would have infringed on the property rights enshrined in the 5th Amendment. Instead, most defined emancipation timeframes for the offspring of enslaved people. For example, in 1778 Connecticut passed a law beginning gradual emancipation of slaves by having newborns achieve freedom at age 25 for men, 21 for women. Because the importation of slaves was banned in 1808 these measures were destined to end slavery in those States over time.