What's in a name? In the case of Leo XIV, lessons in bridging historical shifts

Vatican City: What's in a name? A lot it turns out.

Matteo Bruni, a Vatican spokesperson, told reporters Thursday that Cardinal Robert Francis Prevost's choice to be called Pope Leo XIV had been a clear and deliberate reference to the last Leo, who led during a difficult time for the Roman Catholic Church and helped marshal it into the modern world.

Leo XIII -- who was head of the church from 1878 to 1903, one of the longest reigns in papal history -- is known for his 1891 encyclical "Rerum Novarum," which strongly defended the rights of working people to a living wage and set the tone for the church's modern social doctrine. He became known as the "pope of the workers."

"Addressing the rising socialist threat -- as the church saw it in the late 19th century," Leo XIII "called on the church to reach out to a working class and to basically try to ameliorate some of these goals of capitalism and to benefit the working class and work out a amicable relationship between capital and labor," said David I. Kertzer, a professor at Brown University whose book "Prisoner of the Vatican" examined the role of Leo XIII's predecessor, Pius IX, the last sovereign ruler of the Papal States. "In that sense," Leo XIII is "seen as a kind of connection between the premodern and the modern church."

"The choice of name is a moderate reference, in that Leo XIII was a premodern pope and conservative in many ways, but he was also a transitional figure reaching out to the poor," Kertzer said. "You could say he was a middle-of-the-roader." The selection of the name Leo XIV "seems like a choice of following Francis, but taking the edges off," he added.

Leo XIII was a strong pope who was "very much engaged in the issues of his time," said Robert Orsi, a professor of religious studies and history at Northwestern University. "He responded with authority and compassion to the industrial era" and defended workers' rights and labor organizations.

Choosing to be called Leo XIV could signal the new pope's intention "to equally engage the issues of his time," Orsi said.

Pope Leo XIV referred to the notion of a global church open to the world in his first address to the faithful Thursday, which Orsi said might be a signal "that he'll be challenging resurgent nationalism everywhere in the world."

Bruni, the Vatican spokesperson, said that choosing the name of a pope associated with the church's modern doctrine "was clearly a reference to the lives of men and women, to their work -- even in an age marked by artificial intelligence."

Leo XIII began his reign with the papacy having lost its temporal power when the Papal States it had ruled for hundreds of years were annexed by a unifying Italy in 1870. He sought to reinforce that the role retained a moral authority that reached beyond national borders, said Roberto Rusconi, a church historian.

Rusconi added that Leo XIII had also deepened devotion to the Virgin Mary, writing 11 encyclicals on the rosary, the cycle of prayers invoking Mary that Catholics count out on rosary beads. Leo XIV recited the rosary at the end of his first address Thursday.

Leo XIII was the first pope to appear on film. He founded the Vatican Observatory, a research institute, as a signal of the church's openness to science. "It must be clear that the Church and its pastors do not oppose true and sound science, both human and divine, but that they embrace, encourage and promote it with all possible commitment," he wrote.