Why Did Pope Leo XIV Apologize for Slavery?

 

In his first encyclical—a document on artificial intelligence—the Pope paused to make a concrete confession about the Church’s own role in slavery. Here is why it belongs there.

 

by CAPP-USA

 

In Magnifica Humanitas, Pope Leo XIV did something striking. In an encyclical on safeguarding the human person in the age of artificial intelligence, he paused to apologize for slavery. (Magnifica Humanitas, 173–179)

Not in passing. Not vaguely. Not merely for the sins of anonymous Christians somewhere in the past. Pope Leo XIV specifically named the Church’s delay in clearly denouncing slavery.

He acknowledged that many individuals and even ecclesiastical institutions had held slaves. He stated that the Apostolic See had, at times, intervened to regulate and legitimize forms of subjugation and, in some cases, the enslavement of “infidels.” He identified several fifteenth-century papal bulls in a footnote.

Then he wrote: “For this, in the name of the Church, I sincerely ask for pardon.” (Magnifica Humanitas, 176)

That raises the obvious question: why here? Why in an encyclical on artificial intelligence?

The answer is that Leo XIV is not simply looking backward. He is using one of the Church’s gravest historical failures on human dignity to sharpen moral discernment in the digital age. (Magnifica Humanitas, 177–179)

The Long and Uneven Historical Arc of Slavery and the Church

The Catholic story on slavery is not simple. It is not accurate to say, “The Church always clearly condemned slavery.” Nor is it accurate to say, “The Church endorsed slavery.” The record is more complicated.

As early as 873, Pope John VIII condemned a concrete instance of enslavement, writing to rulers in Sardinia and ordering that those held in slavery be restored to freedom. This was not yet a fully developed universal doctrine against every form of slavery. It was a specific intervention in a Mediterranean Christian context.

But it matters. It demonstrates early papal opposition to enslavement and strengthens the case that the later fifteenth-century authorizations of conquest and servitude were not inevitable products of Christian doctrine. The tradition already contained the resources for condemning enslavement. They were simply not applied consistently.

That inconsistency becomes especially clear in the fifteenth century.

In 1435, Pope Eugenius IV issued Sicut Dudum, condemning the enslavement of Canary Islanders who had become Christian or were approaching baptism. This bull has often served as the “counterargument” in Catholic discussions of slavery: the Church did intervene against enslavement in this case, and demanded liberation under threat of excommunication.

Yet Pope Leo XIV’s footnote groups Sicut Dudum together with Etsi Suscepti 1442, Dum Diversas and Romanus Pontifex.

At first glance this is puzzling, because Sicut Dudum is itself an anti-enslavement intervention. But Leo is not accusing it of complicity. He is citing the fifteenth-century corpus as a whole to show how unstable the Church’s witness was in that era: within the very same decades, papal authority could condemn enslavement in one case and authorize conquest and perpetual servitude in others.

The point is not that every document was wrong, but that the framework was inconsistent—liberation and subjugation coexisting under the same authority. (Magnifica Humanitas, 176, Footnote 174)

The most troubling documents remain Pope Nicholas V’s Dum Diversas (1452) and Romanus Pontifex (1455). These authorized the Portuguese crown to wage war against “Saracens,” pagans, and other enemies of Christ, to seize their possessions, and to reduce persons to perpetual servitude. These are not merely historically awkward documents, and Pope Leo XIV now treats this history as part of a “wound in Christian memory.” (Magnifica Humanitas, 176)

Then comes a significant corrective. In 1537, Pope Paul III’s Sublimis Deus declared that the Indigenous peoples of the Americas—and other peoples yet to be encountered—were human beings capable of receiving the faith, and not to be deprived of liberty or property.

This was a major development. It protected not only the baptized or catechumens but non-Christian Indigenous peoples as human persons with rights to liberty and property. It directly undercut the logic later associated with conquest and enslavement.

In 1839, Pope Gregory XVI’s In Supremo Apostolatus condemned the slave trade and warned Christians not to reduce persons to servitude or to defend such practices as permissible.

But even here the story remains complicated. Catholic slaveholding societies often read Gregory’s condemnation narrowly—as aimed primarily at the slave trade rather than as a mandate for immediate emancipation.

The fuller picture, then, is this:

There were real anti-enslavement interventions: Pope John VIII in 873; Eugenius IV’s Sicut Dudum in 1435; Paul III’s Sublimis Deus in 1537; Gregory XVI’s In Supremo Apostolatus in 1839; and Pope Leo XIII’s In Plurimis in 1888, which condemned slavery as a violation of human dignity, contrary to the original order of creation in which all are born free and equal, followed by Catholicae Ecclesiae in 1890, calling on Catholics to support the global movement to end the African slave trade.

But there were also papal acts that empowered conquest, subjugation, and servitude—above all Dum Diversas and Romanus Pontifex.

Pope Leo XIV’s summary is that the Church’s denunciation of slavery was delayed, that practice was inconsistent, and that the full incompatibility of slavery with Christian conscience was long relativized. (Magnifica Humanitas, 176)

It is not accurate to say, “The Church always clearly condemned slavery.” Nor is it accurate to say, “The Church endorsed slavery.”

Does This Touch the Church’s Teaching Authority?

A natural worry follows: if popes authorized enslavement, does Leo’s apology concede that the Church’s teaching office failed, or even erred while teaching infallibly?

It does not, and Leo is careful here.

The fifteenth-century bulls were acts of governance bound to particular political circumstances, not definitive doctrinal pronouncements. They were prudential judgments addressed to specific rulers at a specific time and place; they did not invoke—and did not meet—the conditions for a definitive or ex cathedra teaching binding the whole Church.

These were disciplinary and political documents, open to questioning and criticism, and the Church’s teaching on infallibility is simply not in play.

The Church made the same point in 2023, when it stated that the bulls underlying the so-called Doctrine of Discovery have never been considered expressions of the Catholic faith.

All this matters for reading the apology correctly.

Pope Leo XIV is not confessing that the Church taught error as defined doctrine. He is confessing that those holding ecclesial authority acted contrary to the Gospel they professed, and that the Church was slow—across centuries—to draw out and apply a truth it already possessed.

The failure was one of witness, vigilance, and consistency, not of defined doctrine.

And that is precisely what makes it usable as a warning for the present.

What Did Pope Leo XIV Do That Pope St. John Paul II Did Not?

Pope John Paul II gave the Church the grammar of historical repentance.

In Incarnationis Mysterium, issued for the Great Jubilee of 2000, he called for the “purification of memory.” He taught that the Church must acknowledge the wrongs committed by those who bore the name of Christian.

While present Christians are not personally guilty for every sin of the past, the Church is one Body across time; they cannot simply detach themselves from the burdens of Christian history. The Church must kneel before God, confess its counter-witness, and seek forgiveness. (Pope St. John Paul II, 11)

Pope Leo XIV takes that and applies it concretely to slavery.

He does not merely say that Christians sinned. He says that ecclesial authority itself was implicated in structures that regulated and legitimized subjugation.

He names the delay. He names the role of the Apostolic See. He identifies the relevant papal bulls. He frames the matter as a development in the Church’s understanding of the perennial truths of Revelation. And then he asks pardon in the name of the Church. (Magnifica Humanitas, 176, Footnote 174)

In one sentence: John Paul II supplied the grammar of ecclesial repentance; Leo XIV used it to make a concrete magisterial confession about slavery and the Church’s complicity.

Why Apologize for Slavery in an Encyclical on AI?

This still raises the question: why did Pope Leo XIV bring it up in an encyclical on artificial intelligence?

Because he is not treating slavery as an isolated historical topic. He is using it as a warning.

Pope Leo argues that technology is not neutral in practice. It “takes on the characteristics of those who devise, finance, regulate and use it.” AI can serve human flourishing, but it can also intensify domination, surveillance, exploitation, trafficking, and the reduction of persons to data. (Magnifica Humanitas, 9-10, 170-181)

The central concern of Magnifica Humanitas is human dignity in the age of artificial intelligence.

This is where slavery enters the argument.

For Pope Leo, slavery is the paradigmatic case of delayed doctrinal recognition.

The Church always affirmed the dignity of the human person created in the image of God. Yet it took centuries to recognize, explicitly and universally, that slavery was incompatible with that dignity. In the interim, political, economic, and missionary entanglements compromised the Gospel’s demand. (Magnifica Humanitas, 176)

Leo’s warning is: do not let that happen again.

AI also raises an analogous theological danger. It can reduce persons to instruments—data sources, labor inputs, predictive profiles, market segments, or disposable bodies hidden inside global supply chains.

Pope Leo points to data labeling, content moderation, mineral extraction, child labor, trafficking, platform-enabled exploitation, and new forms of colonial control through data extraction.

The danger here is not that AI is slavery in a simple one-to-one sense. The danger is that old patterns of domination can reappear in technological form.

That is why he says the memory of past Christian blindness before slavery must become a “call to vigilance.” (Magnifica Humanitas, 177)

This is the key to the whole section.

His apology for the Church’s past in regard to slavery is not institutional self-accusation for its own sake. It is moral teaching.

The Church remembers its failure so that it can discern more clearly in the present.

From Old Colonialism to Digital Colonialism

Pope Leo XIV then connects old colonialism to a new digital colonialism.

Old colonialism once dominated lands, labor, and trade. In the digital age, powers can appropriate data: health records, genetic maps, demographic information, epidemiological profiles, behavioral patterns. Pope Leo writes that these have become the new “rare earths” of power. (Magnifica Humanitas, 178) Data becomes a new resource of domination.

Those who control it can shape markets, allocate resources, predict crises, influence policy, and decide which people and regions matter.

This is why the apology belongs in Magnifica Humanitas.

Pope Leo is not changing the subject. He is showing that the same sinful pattern can recur: powerful actors claiming progress while treating vulnerable people as raw material.

The Church once failed to recognize quickly and consistently enough that slavery contradicted the Gospel. Pope Leo is telling us that the Church must not fail again when AI and digital economies create new forms of domination, servitude, trafficking, extraction, and control. (Magnifica Humanitas, 176-179)

The danger is that old patterns of domination can reappear in technological form.

A Theological Point About Slavery

An important theological insight runs through this section: the development of doctrine.

Pope Leo is not saying that human dignity was absent from Christian revelation until the nineteenth century. He says the dignity of every human being was continuously affirmed—every person is created in the image of God. But the Church’s explicit recognition of slavery’s full incompatibility with that dignity came slowly and inconsistently. (Magnifica Humanitas, 176)

This is the Catholic idea of the development of doctrine, given its classic expression by St. John Henry Newman (the newest Doctor of the Church – proclaimed by Pope Leo XIV in 2025): the deposit of faith does not change, but the Church’s grasp of its implications unfolds over time. (An Essay on the Development of Christian Doctrine (London, 1845; rev. ed. 1878) Chapter 1, Section 1, Part 7)

Newman’s insight cuts both ways. It explains how the Church can come to see more clearly—and it also explains how the Church can, for a long stretch, fail to see what its own principles already required. (An Essay on the Development of Christian Doctrine, Chapter 5)

That is a sobering account of development. It means the Church can possess true principles and still fail to see their full implications in history.

It can preach the dignity of the person while tolerating social arrangements that contradict that dignity. It can evangelize while becoming entangled with worldly powers that compromise the Gospel. (Magnifica Humanitas, 176)

This calls for repentance. And it is also a warning.

It is also why the apology sits naturally within the Church’s living social doctrine—the tradition that runs from Rerum Novarum through Quadragesimo Anno and Centesimus Annus and now to Magnifica Humanitas. That teaching develops not because the truth changes, but because each age forces the Church to apply it to new conditions.

The Church’s social doctrine is living — not because the truth changes, but because history forces the Church to draw out the implications of the truth more fully. Every age has its new social question. For Pope Leo XIII, it was industrial capitalism and the condition of labor. For Pope Leo XIV, it is artificial intelligence and the digital reordering of human life. (Magnifica Humanitas, 4-6)

The challenge is for the Church to see clearly enough, soon enough.

So, Why Did Pope Leo XIV Apologize For Slavery?

Because he needed the Church’s morally serious failure on human dignity to become a lens for the AI age.

He apologized because memory without repentance is evasion, and repentance without vigilance is incomplete: the Church cannot credibly defend human dignity today if it refuses to tell the truth about how slowly and inconsistently it defended human dignity in the past.

And he apologized because the digital age is already producing new forms of subjugation. Hidden labor, trafficking, data extraction, algorithmic control, and digital colonialism are not distant possibilities.

They are already part of the architecture of our technological world. (Magnifica Humanitas, 173-179)

John Paul II’s purification of memory looked backward in repentance. Leo XIV looks backward in order to sharpen present discernment. His message is, in effect: we once failed to recognize quickly enough that slavery was incompatible with the Gospel; we must not repeat that failure when new technologies create new forms of domination.

That is the “why” of the apology. It is not a detour from the encyclical. It is one of its keys.

References

 

 

1. Pope Leo XIV, Magnifica Humanitas (15 May 2026), especially paragraphs 173–179 and footnotes 174–176.
2. John VIII’s 873 intervention: Denzinger–Hünermann no. 668; see also Encyclopedia.com, “Slavery, II (And the Church).”
3. John Paul II, Incarnationis Mysterium (1998), especially paragraph 11 on the purification of memory.
4. Eugenius IV, Sicut Dudum (13 January 1435).
5. Nicholas V, Dum Diversas (18 June 1452).
6. Nicholas V, Romanus Pontifex (8 January 1455).
7. Paul III, Sublimis Deus (1537).
8. Gregory XVI, In Supremo Apostolatus (1839).
9. Leo XIII, In Plurimis (1888); Catholicae Ecclesiae (1890).
10. Dicasteries for Culture and Education and for Promoting Integral Human Development, Joint Statement on the “Doctrine of Discovery” (30 March 2023).