Let us continue our survey of illicit promises, shall we? Can you think of an example of a perfectly legal bargain whose subject matter is nevertheless immoral? What about the Atlantic slave trade? Prior to 1807, when Great Britain and the United States enacted laws abolishing the slave trade, an inhumane and shameful slave trade often operated within a legal framework. By way of example, the importation of African captives into the new world colonies of Spain was based on a special contract called the asiento de negros–a royal license to traffic in human slaves. In brief, these slave trade contracts granted legal permission to certain individuals or merchants to transport and sell a fixed number of enslaved Africans to the Spanish colonies in the Americas. At one point (1713-1750), the British Government owned the legal rights to the Spanish asiento. Specifically, Article X of the 1713 Treaty of Utrecht between Spain and Great Britain granted to the latter the legal rights to the asiento or slave trade between Africa and Spanish America. (Although Britain transferred its rights under this asiento to the South Sea Company, Britain owned shares in this company.) The slave trade thus poses a moral and legal puzzle: the possibility of legal but immoral promises. Usually, a legal promise does not pose any difficult moral issues, but what is the status of a lawful contract that involves immoral conduct?