Catholic Church and slavery

The issue of slavery was one that was historically treated with concern by the Catholic Church. Throughout most of human history, slavery has been practised and accepted by many cultures and religions around the world. Certain passages in the Old Testament sanctioned forms of slavery. After the legalisation of Christianity under the Roman empire, there was a growing sentiment that many kinds of slavery were not compatible with Christian conceptions of charity and justice; some argued against all forms of slavery while others, including the influential Thomas Aquinas, argued the case for slavery subject to certain restrictions. The Christian west did succeed in almost entirely enforcing that a free Christian could not be enslaved, for example when a captive in war, but this itself was subject to continual improvement and was not consistently applied throughout history. The Middle Ages also witnessed the emergence of orders of monks such as the Mercedarians who were founded for the purpose of ransoming Christian slaves. By the end of the Medieval period, enslavement of Christians had been largely abolished throughout Europe although enslavement of non-Christians remained permissible, and had seen a revival in Spain and Portugal.

Although some Catholic clergy, religious orders and Popes owned slaves, and the naval galleys of the Papal States were to use captured Muslim galley slaves, Roman Catholic teaching began to turn more strongly against "unjust" forms of slavery in general, beginning in 1435, prohibiting the enslavement of the recently baptised, culminating in pronouncements by Pope Paul III in 1537.

One form of slavery that several Popes in this era did consider "just" was the enslavement of Africans in wars in retaliation for the Islamic Invasion of Constantinople. Papal decrees of this era would later play a role in the Spanish Empire, including Catholic Monarchs of Ferdinand and Isabella, and the Portuguese Empire importing large numbers of African slaves to the Americas. Slavery in the U.S. also originated with these decrees, dating from prior to the English Reformation and Enlightenment, and was used by Catholic Justice of United States Supreme Court Roger Taney to justify the Dred Scott decision.

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