Pope Leo XIV explained the choice himself, on 10 May 2025, two days after his election, in his first address to the College of Cardinals. He named Leo XIII, Rerum Novarum and the first industrial revolution, and then he named artificial intelligence. The encyclical he signed a year later on Rerum Novarum‘s anniversary was announced, in substance, in that paragraph.
What he said
“Sensing myself called to continue in this same path, I chose to take the name Leo XIV. There are different reasons for this, but mainly because Pope Leo XIII in his historic Encyclical Rerum Novarum addressed the social question in the context of the first great industrial revolution. In our own day, the Church offers to everyone the treasury of her social teaching in response to another industrial revolution and to developments in the field of artificial intelligence that pose new challenges for the defence of human dignity, justice and labour.”
Read the last clause with care. It is a list and the order of the items on that list matters: human dignity, justice, and labour. Those are the three headings of the encyclical that followed.
Why this is worth more than a piece of trivia
A papal name is a statement of program, and this one was unusually explicit. Popes often let the meaning of a name emerge. Leo XIV said what he intended two days in, named the technology, and identified the tradition he meant to apply to it.
Then he did it. He signed Magnifica Humanitas on 15 May 2026, the 135th anniversary of Rerum Novarum (§3), and structured it as an application of social doctrine rather than as a technology paper.
The choice also tells you what he did not mean. He did not take a name signaling a break, a restoration or a personal devotion. He took the name of the pope who established the modern method of Catholic social teaching, at the moment that method faced its next test.
The Leo XIII he is invoking
It is worth knowing which Leo XIII this is, because there are several available. Leo XIII reigned from 1878 to 1903 and did a great deal besides Rerum Novarum, including Aeterni Patris, which restored the study of Saint Thomas Aquinas. Leo XIV points specifically at the social encyclical and at what it did: it gave impetus to the reflection on society, economy and politics now known as the Social Doctrine of the Church (§3).
He also recalls the objection Leo XIII faced, which has a modern equivalent. Some argued the Church “should not waste energy on worldly matters, but instead focus on communicating the message of eternal life.” Leo XIII answered “with realism and wisdom, saying that the proclamation of the Gospel cannot overlook the concrete lives of people” (§3).
Anyone inclined to think a pope should stay out of questions about technology and labour is making an argument that was made in 1891 and answered then.
What the name commits him to
Taking a name is taking on a standard. Rerum Novarum is remembered because it was specific. It named wages, hours, associations and property, and it did so when doing so was costly. A document invoking it while staying at the level of general principle would fall short of its own claim.
Magnifica Humanitas is specific in the same way in places. It asks legislators for age limits on children’s devices and for holding platforms accountable rather than families (§142). It says lethal decisions may not be delegated to machines (§198). It says data ownership “cannot be left solely in private hands” (§108). Those are the kinds of claims Leo XIII made, in the register he made them.
The address is Leo XIV, Address to the College of Cardinals, 10 May 2025. Section references are to Magnifica Humanitas (15 May 2026). The full guide is here.
Related
The Catholic Citizen starts with this encyclical
Module 1 of The Catholic Citizen works through Magnifica Humanitas over four Thursdays — human dignity, moral responsibility, work, and who owns the common inheritance of data — one issue a week, every claim cited by paragraph number. The curriculum page lists the module in full. Free reflections on the daily Mass readings arrive Saturdays.
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