THE preconditions on the eastern side of the Atlantic helped shape the development of the transatlantic slave trade and slavery in the Americas. The Old World background features were numerous, and there are many facets that could be considered. To deal with all of them would require more space and time than is available. Nevertheless, it is possible to address the most significant features. These include the decision to use imported slaves in the Americas, the role of disease in that decision, the distinctions between small-scale and large-scale slavery, the role of sugar, and the availability of black slaves.

At the time of their initial contacts with the peoples of the Americas, both the Spaniards and the Portuguese hoped to make use of the factory (feitoria, factoría) system, in which they would establish links with an existing trading network and exchange their goods for those of the local peoples. This was the policy the Portuguese had successfully followed as they progressed down the west coast of Africa. However, such a strategy depended on having a number of conditions present. These include a sufficiently developed trading network among the indigenous peoples and the presence of goods and commodities that the Europeans could acquire through exchange. Those conditions were present in Africa, but they were missing in the New World.

As the Spaniards explored and conquered the islands of the Caribbean and the American mainland, they found that they could not establish a commercial network of trading factories, because no preexisting trading networks were available.