As I understand it, landowners in 17th century North and South America and in the assorted islands initially adopted the wholesale enslavement of blacks out of economic motives. Life was becoming less dangerous for their indentured servants, who were now living long enough to complete their contracts and go out on their own. Faced with a labor shortage, they began importing human beings from Africa as slaves. There was already an established slave trade in Africa, where they often enslaved prisoners of war and the like, as did almost all cultures at one point or another. Using Africans meant that you could always tell if an individual was a slave, a much harder proposition than if you had an enslaved Scot or Italian on your plantation. Black skin = somebody's property, no questions needed. Most of the talk of the inferiority of certain racial groups - however much they were later fervently accepted - were initially ad hoc justifications for a primarily economic arrangement.
I have no time for lies and fantasy, and neither should you. Enjoy or die.
-John Lydon