The cellphone of the leader of the Order of St. Augustine, the Rev. Alejandro Moral Antón, buzzed for what seemed like the hundredth time, and he jumped. He had been up since 2:30 a.m. fielding calls, trying to explain to people across the globe how his order, the one that formed Pope Leo XIV, would shape the papacy.

This time, it was his dentist. He had missed an appointment.

“You know what’s happening?” he told the dentist on Monday afternoon in Rome. “The new pope is an Augustinian!”

The world’s sudden interest in the small order of fewer than 3,000 members had forced Father Moral Antón, an affable, 69-year-old Spaniard, to distill Augustinians’ principles and spiritual ideals to their essence. Charity, truth and unity, he recited in Latin and translated into Spanish.

Pope Leo, formerly Cardinal Robert Francis Prevost, is an American with Peruvian citizenship, but his identity may have been most deeply molded by his connection to the Augustinians, which began when he was 14 and led to his ordination in 1982 as an Augustinian priest. He moved to Peru as an Augustinian missionary and eventually ran the order for 12 years from Rome. In that position, he developed extensive international connections that helped raise his profile last week in the conclave of cardinals who elected him.

As the first Augustinian friar to become pope, Leo is expected by Augustinians to emphasize missionary outreach and the importance of listening widely before making decisions, both central to the Augustinian way of life.

“The Holy Father will certainly be inspired by this search for communion and dialogue,” said Pierantonio Piatti, a historian of Augustinians with the Pontifical Committee for Historical Sciences, a Vatican office. That would mesh with the concept of “synodality,” fulfilling Francis’ vision of a church that brings bishops and lay people together to make big decisions.

“The other great element of Augustinian spirituality,” Dr. Piatti added, is a “search for balance between action and contemplation, between contemplation and action.”

In part because of their small size, Augustinian priests are a tight-knit community around the world, and many have encountered Leo over the years.

“Even when we disagree on something like politics, we have no trouble talking to one another,” said Father Allan Fitzgerald, 84, an Augustinian priest and longtime professor at Villanova University northwest of Philadelphia, which Leo graduated from in 1977. “I think we are, in some ways, an image of the U.S. There is certainly a whole swath of us that is to one side and to the other. Even if we can’t talk directly about politics, we are still able to talk about things that matter.”

The order was founded in 1244, when Pope Innocent IV united groups of hermits in service to the church as a community of friars. The group committed to a lifestyle of poverty, along with a mix of contemplation and pastoral service.

Augustinians take their name from one of Christianity’s most important early theologians, Augustine, the Bishop of Hippo, who was born in what is now Algeria in the fourth century. He is perhaps most famous for an autobiographical work called “Confessions,” which in part details his conversion to Christianity after an immoral youth.

The order’s place in the broader Roman Catholic Church was threatened by one of its most prominent 16th-century members, Martin Luther, whose calls for reform in the church ended up leading to the Protestant Reformation.

Augustine also wrote a guide to religious life that became the cornerstone of the Augustinian order. Its members commit to “live together in harmony, being of one mind and one heart on the way to God.” Leo’s new coat of arms reflects that heritage, displaying the Latin motto “In illo uno unum,” or “In the One, we are one.”

Augustinians are generally far less known compared with larger groups like the Jesuits and Franciscans. Part of that has to do with the personality and style of the orders, Father Fitzgerald said.

“If you are a Jesuit, you are very good at telling people who you are,” he said. “Augustinians are not great at telling people who we are. I think it is unusual for us to be self-promoting.”

In the years after he became head, or prior general, of the order in 2001, Leo tried to share on a global stage the ideas and practices for missionary outreach that he had developed in Peru.

He outlined his theological underpinnings in a speech in Rome in 2023. Mission is a means of carrying out the church’s fundamental duty of evangelization, he said. Without this perspective, charity work by the church becomes little more than “humanitarian action,” which, while important, will not be distinctively Christian.

“On the contrary, when we help each other to constantly remind ourselves that our primary mission is evangelization, it does not matter whether our resources are small or large because the fundamental thing is already given,” he said.

“To evangelize means, among other things, to be willing to leave the comfort zones, the comfortable bourgeois life,” he said, in an apparent nod to his life-changing decision to leave his life in the United States for a missionary posting in northwestern Peru in 1985. That background appears to have figured in the cardinals’ deliberations during the conclave, since missionary outreach was a key element of Francis’ vision.

Leo once told the Italian broadcaster RAI that he had met “my religious family, the Augustinians,” as a teenager, prompting his decision to leave Chicago for an Augustinian junior-seminary boarding school in Michigan. There, he said, he got to learn about “the importance of friendship, the importance of life in community.”

“I believe it is very important to promote communion in the church,” Leo explained in 2023 to Vatican News. “As an Augustinian, for me promoting unity and communion is fundamental.”

On Saturday, Leo made an unannounced visit to Our Lady of Good Counsel in Genazzano, an Augustinian sanctuary outside Rome. On Monday, he invoked St. Augustine in remarks to journalists gathered in Vatican City, saying that the present times were challenging, difficult to navigate and not easy to recount to the public.

“They demand that each one of us, in our different roles and services, never give in to mediocrity,” he said. “St. Augustine reminds of this when he said: ‘Let us live well and the times will be good. We are the times.’”

He cited one of the saint’s sermons that alluded to how people can choose to make the most of tough circumstances, Father Moral Antón said: “We are the ones who have to live a good life to change the times.”

“We need to stop and reflect,” he added. “Because we live well, we eat well, we have pleasures, but are you happy? And people say, ‘I’m not happy.’ Let’s look, then, at where happiness lies — within — and then change.”

Father Moral Antón, who missed his dental appointment on Monday, was sitting in a small room in the Augustinian College of St. Monica, on a hillside across the street from St. Peter’s Basilica, where the new pope has played tennis for years on a court with a view of the iconic dome. Father Moral Antón and Leo, who are the same age, studied together in the college decades ago; the father was Leo’s deputy when he ran the order and succeeded him in the top job.

In the days since Leo became pope, Augustinian friars have shared stories of meeting him during his past travels. One vicar in Kenya sent Father Moral Antón photos of a trip he and Leo took to the African country many years ago.

“Being an Augustinian means being pretty open,” Father Moral Antón said, adding that, compared to other orders, theirs does not have “very rigid norms.”

“It’s about eternal friendship, friends, wanting to walk with friends and find truth with friends,” he said. “Wanting to live in the world, to live life — but with friends, with people who love you, with whom you love.”

“It is not always something you find,” he added, “but, well, that’s the ideal.”

Emma Bubola, Elizabeth Dias and Jason Horowitz contributed reporting.