In the 1500s, a Catholic monk in Spanish America stopped the slaughter of enslaved Native Americans. This merciful act had some terrible consequences, for it doomed Africans to centuries of slavery. How could this have happened?

Spain's colonies in Latin America had an enormous need for labor. Their gold and silver mines needed miners. Their plantations and cattle ranches needed field hands. The Spanish first enslaved Native Americans, but the Indians suffered terribly from European diseases and miserable working conditions. A Spanish monk named Bartolome de las Casas exposed that situation. He brought about gentler treatment of the Indians.

With Native Americans off-limits, the Spanish had to look elsewhere for farm and mine workers. So they began importing Africans, who were immune to many tropical diseases. The Spanish imported millions of Africans—more than the British and Americans brought to the United States.

Over time, many of these slaves were freed. By the 1700s, there were more free blacks than slaves in Spanish America.