The document, titled Magnifica Humanitas, is the first encyclical of the American-born pontiff and outlines a comprehensive ethical framework for the governance of artificial intelligence. Leo argued that governments, technology companies and society must ensure that AI serves humanity rather than concentrated political, military or commercial interests.

The publication had been closely anticipated since the pope declared shortly after his election that artificial intelligence represented the most significant challenge facing humanity. In the text, he warned against what he described as a “culture of power” driving the global race to develop increasingly sophisticated AI systems.

Leo directed particular criticism at the use of AI in warfare, declaring that irreversible decisions involving the use of lethal force should never be delegated to autonomous systems. He argued that accountability for military actions must remain firmly in human hands and called for greater transparency in the development and deployment of AI-enabled weapons.

The encyclical also questioned whether traditional Catholic principles governing the ethical use of force remain adequate in an era of rapidly advancing military technologies.

Leo suggested that technological transformations in warfare require renewed moral reflection and updated international safeguards.Beyond security concerns, the pope warned about the concentration of data, wealth and influence among a small number of technology companies.

He argued that ethical commitments by private firms alone were insufficient and called for robust legal frameworks, independent oversight mechanisms and stronger democratic regulation.The Vatican formally presented the document at an event that included participation from representatives of anthropic, one of the world’s leading artificial intelligence companies.

The company’s involvement reflected the Vatican’s long-running engagement with Silicon Valley on the social and ethical implications of emerging technologies.Despite hosting technology executives, Leo repeatedly emphasized that public authorities must not abdicate responsibility for regulating AI.

He urged developers and policymakers to slow the pace of deployment when necessary and to prioritize the common good over commercial gain.The pope framed the AI revolution within the broader tradition of Catholic social teaching. He linked the challenges posed by artificial intelligence to those addressed in Rerum Novarum, the historic 1891 encyclical issued by Pope Leo XIII that examined workers’ rights and the social consequences of industrialization.

Signed on the 135th anniversary of that document, Magnifica Humanitas argues that AI raises comparable questions about labor, economic power and human dignity. Leo warned that the pursuit of efficiency and profit must not come at the expense of workers whose livelihoods could be displaced by automation.

Technology experts and scholars said the encyclical is likely to become an influential reference point in debates surrounding artificial intelligence governance. Taylor Black said the rapid evolution of AI was already prompting deeper questions about the meaning of human identity, while Paolo Carozza described the document as a potentially defining contribution to discussions about the relationship between technology and society.

The manifesto also contained a historic acknowledgment of the Catholic Church’s role in legitimizing slavery during earlier centuries of European expansion. Leo issued the first papal apology specifically addressing the Holy See’s involvement in granting rulers authority to subjugate and enslave non-Christians, extending the document’s focus beyond technology to broader questions of historical responsibility and human dignity.

The encyclical marks the most comprehensive intervention by the Vatican to date on artificial intelligence and places the Catholic Church at the center of a growing global debate over how emerging technologies should be governed as they reshape economies, societies and international security.