It is a painful fact that capitalism and the great bourgeois revolutions of the West coincided with the institutionalization and spread of chattel slavery. Equally painful, if not as well known, is the fact that the idea of race, as we understand it today, is a legacy of the Enlightenment—as are all the nefarious ideologies of superiority built on that idea.
Medieval Christians believed that all human beings were descendants of Adam, and thus that all humans are essentially the same beings in different states of grace. As the scientific revolution developed and turned toward biblical criticism, theories that humanoid beings must have existed prior to Adam became popular. The popularity of such theories was linked to the recent discovery of the New World.
The reaction of believing Christians to the discovery of new peoples was a mixed bag: either zealous missionary work or a prefiguration of "manifest destiny." Both reactions sprang from the idea that these new people groups must either be the "lost tribes" of Israel or else descendants of Ham, Shem, or Japheth. The secular reaction to the discovery of new peoples was one of scientific curiosity and hope of discovering new species.
Nowhere was this contrast more evident than on the voyage of the Beagle. Charles Darwin was intrigued to investigate the preservation of favored races in the struggle for life. His ship-mate Richard Matthews was on a mission to bring Christianity and civilized life to the inhabitants of Tierra del Fuego. While Matthews' mission was largely unsuccessful on the archipelago, the change which had taken place in the three converted Fuegian men aboard their ship was enough to influence the opinion of Darwin:
"... in contradiction of what has often been stated, 3 years has been sufficient to change savages, into, as far as habits go, complete & voluntary Europæans. — York, who was a full grown man & with a strong violent mind, will I am certain in every respect live as far as his means go, like an Englishman."
Thank God for the lingering influence of Christianity on the West. Who knows how much darker the history of modernity might have been without it.