To read part one of this history, click here. To read the post that inspired this series, click here.


Magisterial authorities would continue to endorse real world practices of slavery throughout the medieval era.

In this vein, magisterial authorities recognized four legitimate reasons-then called “titles”-for which one person could enslave another:

  1. As punishment for a capital crime.
  2. As a result of capture on the battlefield while fighting an unjust war.
  3. As repayment for debt.
  4. Through purchase from a slave trader who acquired the slave legitimately.
  5. In the case of the centuries’ long battle between Christian and Muslim kingdoms for control of the Iberian peninsula: for being a foreign Muslim.

These titles may seem random and arbitrary to us, but each followed the logic of slavery.

Enemy soldiers and capital convicts alike both deserved death but were mercifully allowed to live. Since they lived because of their masters, they therefore lived for them. Put another way, a master owned a slave’s life because a slave owed him her life.

What about the Muslims? More than simply generic religious bigotry positioned them as especially enslaveable. Purportedly descended from apostate Christians, they were engaged in theological rebellion simply by existing. They were theologically what enemy soldiers and capital convicts were sociopolitically.

Informed by this traditional Catholic teaching about slavery, in the fifteenth century, Pope Alexander VI gave all of Africa to Portugal and America to Spain with the explicit command to enslave all those who didn’t bow down to Iberian authority.

During the sixteenth century, Portugal grew increasingly prosperous due to its role as the leading trader in African slaves

Although subsequent popes would disagree with Alexander about the inherent enslaveability of indigenous people, they did not disagreewith him about the possible goodness of slavery itself.

Indeed, even while condemning the enslavement of indigenous people, they tolerated the enslavement of African-descended people.

Even as Africanized slavery played an increasingly important role in the Catholic countries of first Portugal and Spain and then France, the Catholic magisterium expressed remarkably little doubt about slavery’s circumstantial goodness. Magisterial authorities held tight to their beliefs about slavery.

Not even the great advocate of Indian liberation, Bartolomé de las Casas, thought slavery was always wrong: he railed against the enslavement of the Indians but did not always oppose the enslavement of Africans or the Turks.

Although he would one day regret his naive acceptance of the trade in African slaves, he never changed his mind about the Turks. Locked in a state of war with Christian Europe, the Turks were enemy combatants and therefore enslaveable (231). He disagreed not with Catholic teaching about slavery, but merely its application to this specific case.

I mention Las Casas not to demonize him, but simply to outline the limits of the medieval and early modern moral imagination. Because slavery seems so obviously evil to us today, we may struggle to appreciate just how commonsensical it once seemed. We can easily underestimate the the distance that has been traveled from then to now.

Pope Gregory XVI did finally unequivocally condemn the African slave tradein 1839, more than three hundred years after it began. Unfortunately, however, this encyclical did not offer an opinion on the simple ownership of slaves.

Papal opinion about slavery sometimes moved backwards. Less than thirty years later, Pope Pius IX insisted that it was not against “the divine law” to buy or sell a slave.

**And, finally, in a 1929 encyclical about Christian education, Pope Pius XI seems to identify slave ownership as a part of a well functioning social order (par. 53).

We take the obviousness of slavery’s evil for granted, but, although it may be hard for us to believe, the Catholic magisterium did not condemn slavery itself until the Second Vatican Council.

**UPDATE (June 10th, 2019, 5:39 p.m.) On Twitter, Professor Kevin M. Clarke convinced me that this was not really very good evidence for what I’m trying to prove here so I decided to remove it but still leave a record of what I had originally wrote. I am very grateful for his intervention!

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