VATICAN CITY (AP) — Pope Leo XIV made a historic apology on Monday for the Holy See's role in legitimizing slavery and for having failed to condemn it for centuries, calling the Vatican's record a "wound in Christian memory."

Past popes have apologized for Christians' involvement in the trans-Atlantic slave trade. But no pope had ever publicly acknowledged, much less apologized for, the role that past popes played in giving European sovereigns explicit authority to subjugate and enslave "infidels."

History's first U.S.-born pope, whose family history includes both enslaved people and slave owners, delivered the apology in his first encyclical, "Magnifica Humanitas," (Magnificent Humanity), which was released Monday.

The sweeping manifesto is about safeguarding humanity in an era of increasing reliance on artificial intelligence. Leo raised the slave trade in relation to what he called the new forms of slavery and colonialism that the digital revolution is fueling.

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Black American Catholics, activists and scholars have long called for the Holy See to atone for its role in the colonial-era trade in human beings, beyond generic apologies for the involvement of individual Christians.

"It is impossible not to feel deep sorrow when contemplating the immense suffering and humiliation endured by so many in stark contrast to their immeasurable dignity as persons infinitely loved by the Lord," Leo wrote. "For this, in the name of the church, I sincerely ask for pardon."

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Shannen Dee Williams, historian at the University of Dayton and author of the 2022 history of American Black Catholic nuns, "Subversive Habits," welcomed the apology as a "monumental step toward the kind of essential truth-telling and reparation that many Catholics have prayed and worked to witness."

"The Catholic Church has never been an innocent bystander in the history of white supremacy," said Williams. "Black Catholics have waited a long time to hear the Vatican speak honestly about the church's leading roles in the trans-Atlantic slave trade and chattel slavery--and thus by extension the enduring systems of anti-Black racism in the world today."

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Centuries of legitimizing slavery for European colonizers

The Vatican has insisted that it always upheld the dignity of all human beings as children of God. But a series of 15th-century directives from the Vatican authorized Portuguese sovereigns to conquer Africa and the Americas and enslave non-Christians.

In 1452, for example, Pope Nicholas V issued the papal bull Dum Diversas, which gave the Portuguese king and his successors the right "to invade, conquer, fight and subjugate" and take all possessions — including land — of "Saracens, and pagans, and other infidels, and enemies of the name of Christ" anywhere.

The bull also gave the Portuguese permission "to reduce their persons to perpetual slavery."

That bull and another issued three years later, Romanus Pontifex, formed the basis of the Doctrine of Discovery, the theory that legitimized the colonial-era seizure of land in Africa and the Americas.

Nicholas V's permissions to the Portuguese were confirmed or renewed by Pope Callixtus III in 1456, Pope Sixtus IV in 1481 and Pope Leo X in 1514, according to the Rev. Christopher J. Kellerman, a Jesuit priest and author of "All Oppression Shall Cease: A History of Slavery, Abolitionism, and the Catholic Church."

Spanish kings received the rights for the Americas.

In 2023, the Vatican formally repudiated the Doctrine of Discovery, but it never formally rescinded, abrogated or rejected the bulls themselves. The Vatican insists that a later bull, Sublimis Deus in 1537, reaffirmed that Indigenous peoples shouldn't be deprived of their liberty or the possession of their property, and weren't to be enslaved.

Holy See late to condemn slavery, Leo says

In his encyclical, Leo recalled that his namesake, Pope Leo XIII, was the first pope to explicitly condemn slavery in 1888, long after many countries had abolished it. Before that, in antiquity and the Middle Ages, church institutions and even popes — Gregory the Great — had slaves, Kellerman said.

In acknowledging the 15th century papal bulls, Leo wrote in his encyclical: "Already in the early modern period, the Apostolic See of Rome, responding to the requests of sovereigns, intervened several times in order to regulate and legitimize forms of subjugation, and, in certain cases, including the enslavement of 'infidels.'"

Leo said it wasn't possible to judge the morality of the decisions with today's standards.

"Yet neither can we deny or diminish the delay with which both society and the church came to denounce the scourge of slavery," he said.

The pope said that the church has long affirmed the dignity of every human being as the basis of its doctrine, "even if it took eighteen centuries for its full incompatibility with slavery to be explicitly recognized."

"This constitutes a wound in Christian memory, one from which we cannot consider ourselves detached," he said.

Leo said that the church must firmly condemn all forms of trafficking related to the digital technological revolution "if we want to avoid the need to ask for pardon again in the future for having failed to respect the treasure of human dignity that is required by our faith."

Anthea Butler, senior fellow at the Koch History Center, Oxford University, said Leo needed to acknowledge and atone for the church's complicity in historic slavery if he wanted to credibly "speak to the current issues of technological enslavement."

"For descendants of enslaved persons, this is once again a much needed apology from the pope," said Butler, who is Black.

Leo's own family history and past apologies

Kellerman, the scholar, welcomed Leo's apology but said more needs to be done to further acknowledge how the Catholic Church legitimized and expanded slavery.

"Pope Leo has strengthened the moral credibility of the church with this admission and apology today," he told The Associated Press. "Hopefully a future document will explain in more detail the church's involvement with slaveholding. As a scholar I have some quibbles with the wording, but this is a truly remarkable moment."

During a 1985 visit to Cameroon, St. John Paul II asked forgiveness of Africans for the slave trade on behalf of Christians who participated in it, but not the popes. In a 1992 visit to Goree Island, Senegal, which was the largest slave-trading center in West Africa, he denounced the injustice of slavery and called it a "tragedy of a civilization that called itself Christian."

According to genealogical research published by Henry Louis Gates Jr., 17 of Leo's American ancestors were Black, listed in census records as mulatto, Black, Creole or a free person of color. His family tree includes slaveholders and enslaved people, Gates wrote in The New York Times.

During a visit to Angola last month, Leo prayed at a Catholic shrine at the site of an important hub of the African slave trade during Portugal's colonial rule. While at the Sanctuary of Mama Muxima, Leo recalled the "sorrow and great suffering" Angolans endured for centuries, but he didn't refer specifically to slavery.

Winfield reported from Middletown, Connecticut.