Contrary to what we may think we know about Christianity, Christians did not stand up for the freedom or fair treatment of slaves in medieval Europe. In defiance of our widely-embraced American concepts of virtue, morality, love, compassion, fairness, freedom, racial and social equity, personal dignity, and even basic human decency, Christians eagerly embraced slavery.
Christian churches owned hundreds of slaves. Bishops, popes, and monasteries kept them busy working the land for profit. The Church's profit.
Not that Christians were completely heartless. They drew the line at enslaving fellow Christians. But their limits had limits. Catholics had no problem with Eastern Orthodox Christians being enslaved.
Learn more about the American Civil War here.