Pope Leo XIV’s First Encyclical Letter
The first encyclical of Pope Leo XIV is expected to be signed next week, on May 15, Germany’s KNA news agency has reported, citing “various Vatican sources.” The date places the new Pope in direct continuity with a tradition of social encyclicals that helped define the Church’s engagement with the modern world.
The precedent begins with Pope Leo XIII and his 1891 encyclical Rerum Novarum, released May 15 that year. That document marked the Church’s first systematic response to the upheavals of the industrial revolution, addressing labor rights, private property, and the moral responsibilities of both workers and employers. From it emerged what is now known as Catholic social teaching (or Catholic social doctrine).
The handful of social encyclicals that have been released in the decades since 1891 have often been released on anniversaries of Leo XIII’s encyclical. This year, of course, is the 135th anniversary.
Leo XIV indicated from the beginning that his pontificate was inspired by Pope Leo XIII and that he would continue to address the great changes coming to our world, especially through AI, so it seemed that an encyclical on a May 15 was somehow pre-ordained.
The May 15 encyclicals
Forty years after Rerum Novarum to the day (May 15, 1931), Pope Pius XI deepened Leo XIII’s framework with Quadragesimo Anno. Influenced in part by Jesuit thinker Oswald von Nell-Breuning, the encyclical articulated the principle of subsidiarity and clarified the Church’s critique of socialism, particularly its insufficient regard for the human person and private ownership.
Three decades later, the tradition continued on the same date in 1961, when Pope John XXIII issued Mater et Magistra, advocating greater participation of workers in economic life.
The same pope would add another to the list of social encyclicals, but not on the same date: On April 11, 1963, St. John XXIII released Pacem in Terris.
St. Paul VI followed with Populorum Progressio on March 26, 1967.
But Pope John Paul II returned — or tried to — the anniversary timing.
He released Laborem Exercens on September 14, 1981. It was supposed to have been published on May 15, but was delayed due to the assassination attempt on his life on May 13, 1981. Centesimus Annus, assessing the collapse of communism and offering a nuanced affirmation of the market economy as a generator of prosperity, while insisting on ethical limits, was released “100 years” after Rerum Novarum, released on May 1, 1991.
Magnificent
Reports — and his own comments — suggest that Leo XIV’s encyclical, provisionally titled Magnifica humanitas (Magnificent humanity), will take up questions that are no less consequential today. Artificial intelligence, in particular, raises pressing concerns about human agency, work, and responsibility. The fragility of international law and ongoing conflicts add further urgency.
What distinguishes this moment is not only the subject matter, but the deliberate invocation of history. If he indeed chooses a May 15 release date, Leo XIV signals that the Church’s social teaching is not static. It develops in response to new realities while remaining anchored in enduring principles: the dignity of every person, the priority of the common good, and the moral limits of power.
If the expectations are confirmed, this first encyclical will place Leo XIV within a living tradition — one that continues to speak into the most complex challenges of each age.
From Aleteia — Daniel Esparza – Kathleen N. Hattrup – published on 05/04/26
