How Does a Pope Choose His Name?

The cardinals reached their decision after being in conclave for a little more than 24 hours, and after several rounds of voting. The group of 133 cardinals, the most ever to gather in a conclave, included many who were appointed by Francis and some who did not know one another. That had made reaching a quick consensus a serious challenge, given the broad group of contenders and the splits among them about the future of the church.

Despite his American roots, Cardinal Prevost, a 69-year-old, Chicago-born polyglot, is viewed as a churchman who transcends borders. He served for two decades in Peru, where he became a bishop and a naturalized citizen, then rose to lead his international religious order. Until the death of Francis, he held one of the most influential Vatican posts, running the office that selects and manages bishops globally.

A member of the Order of St. Augustine, he resembles Francis in his commitment to the poor and migrants and to meeting people where they are. He told the Vatican’s official news website last year that “the bishop is not supposed to be a little prince sitting in his kingdom.”

He has spent much of his life outside the United States. Ordained in 1982 at age 27, he received a doctorate in canon law at the Pontifical University of St. Thomas Aquinas in Rome. In Peru, he was a missionary, parish priest, teacher and bishop. As the Augustinians’ leader, he visited orders around the world, and speaks Spanish and Italian.

Often described as reserved and discreet, he would depart stylistically from Francis as pope. Supporters believe he will most likely continue the consultative process started by Francis to invite lay people to meet with bishops.

It is unclear whether he will be as open to gay, lesbian, bisexual and transgender Catholics as Francis was. Although he has not said much recently, in a 2012 address to bishops, he lamented that Western news media and popular culture fostered “sympathy for beliefs and practices that are at odds with the Gospel.” He cited the “homosexual lifestyle” and “alternative families comprised of same-sex partners and their adopted children.”

He, like many other cardinals, has drawn criticism over his dealings with priests accused of sexual abuse.

Francis was the first pope to honor St. Francis of Assisi, whose devotion to humility and care for the poor became central tenets of his papacy. John Paul II picked his name as a tribute to his predecessor, John Paul I, who died after only 33 days in office.

The tradition of selecting a name dates to 533, when a priest named Mercurius — like the Roman god Mercury — was elected pope. Popes had previously been called by their given names, but Mercurius was most likely seen as too pagan, so he became John II.

Choosing the name of another pope could be a nod to that earlier pontiff’s priorities. For example, a John Paul III might focus on doctrinal discipline and social justice, while a Pius XIII might hew closer to tradition. A John XXIV would most likely be seen as a reformist.

The new pope’s name will be announced in Latin from the papal balcony at St. Peter’s Basilica by Cardinal Dominique Mamberti of France, the senior cardinal deacon of the Roman Catholic Church, soon after he declares “Habemus papam,” or “We have a pope.”

In 2013, Francis delighted the faithful by greeting them in Italian with a casual “buonasera,” or “good evening.” He also asked the audience to “pray for me,” which became his signature to end almost all of his speeches, greetings and benedictions. And he led a prayer for his predecessor, Benedict XVI, who had retired.

In his first words, in 2005, Benedict had spread his arms wide and described himself as “a simple, humble worker in the Lord’s vineyard.” The remark was seen as a recognition that his predecessor’s consequential pontificate would be difficult to follow.

The new pope will be expected to speak in Italian, the language in which daily business is conducted at the Vatican. John Paul II, who was Polish, said in his first words, in 1978, that if he did not speak Italian well enough, the faithful should correct his mistakes — a line that quickly endeared him to the public.

New popes sometimes also offer a few words in private to cardinals before greeting the public. John Paul I, who died only 33 days after he was elected, famously told the cardinals, “May God forgive you for what you have done.”

The cardinal (for this conclave, it is Cardinal Dominique Mamberti of France) will then announce the identity of the chosen pope and the name he will adopt as pontiff. Last time, Francis came out onto the balcony about 10 minutes after his identity was announced.

(Should Cardinal Mamberti be chosen as pope, the announcement will be made by Cardinal Mario Zenari of Italy.)

Inside the Apostolic Palace, which contains the Sistine Chapel, there will be a burst of activity in the meantime, as per rules set out in a 1996 Vatican document.

Archbishop Diego Ravelli, in his role as master of papal liturgical celebrations, will draw up a document certifying that the elected cardinal has agreed to become bishop of the church of Rome, true pope and head of the College of Bishops. Should the new pope not be a bishop, he will immediately be ordained.

According to the rules, the voting cardinals then “approach the newly-elected Pope in the prescribed manner, in order to make an act of homage and obedience.”

The pope will next be taken to the Room of Tears, a small chamber just off the Sistine Chapel, where he will put on the white papal cassock for the first time. Garments in three sizes are prepared and kept in the room since no one knows who — or what size — the next pope will be. The shoes come in various sizes, too. (The Room of Tears acquired its name because of accounts of previous popes having become overwhelmed with emotion in the room after their election.)

It is only after the pope has donned the papal vestments that he will emerge on the balcony and greet the public for the first time.

The first rule of papal campaigning is that there is no papal campaigning. In other words, self-aggrandizement and transparent politicking are taboo in the non-campaign campaign. As Vatican experts like to say: Whoever enters the conclave as pope exits a cardinal.

Not always, though. In 2005, Cardinal Joseph Ratzinger, then the dean of the College of Cardinals, gave a humdinger of a funeral homily for Pope John Paul II. He entered the conclave with momentum and emerged on the balcony as Benedict XVI.

Francis had no such prime-time platform for a stump speech. He instead impressed his fellow cardinals with his humbleness and the incisiveness of his remarks at the pre-conclave meetings.

The challenge for the current potential candidates has been to be as adept as Francis in winning support — without seeming to seek it.

This year’s conclave is only the 14th to be held inside the chapel since rules for electing a pontiff were first drafted some 800 years ago, said Ralf van Bühren, who teaches art history at the Pontifical University of Santa Croce in Rome.

The conclave was first held in the chapel in 1492. Then for more than 300 years, conclaves were held in different spaces in the Apostolic Palace, the papal residence. It was not until 1878 that the church again started holding the papal elections in the Sistine Chapel. And it did not become the official site for the conclave until 1996, when Pope John Paul II drafted new rules for papal elections, noted Barbara Jatta, the director of the Vatican Museums.

In the early centuries of the church, the popes were elected by acclamation — a kind of group voice vote — and the clergy as well as the population of Rome could participate. Gradually, voting rights were restricted to the top ranks of the clergy, though external interference from monarchs and aristocrats was common.

The longest conclave in history lasted 33 months, between Nov. 29, 1268, and Sept. 1, 1271. It prompted Gregory X, the pontiff who emerged from that election, to draw up rules that were first used in 1276. These were adjusted over the years, overhauled by John Paul II, and tweaked by Benedict XVI.

Conclave comes from “cum clave,” Latin for with a key, and the cardinals remained sequestered until a pope was chosen. Small, hastily built cubicles were erected in the Sistine Chapel and surrounding halls and rooms. Each cardinal was allowed an aide or two, though since space was scarce, the aides were often forced to sleep on makeshift lofts above the cubicles.

There were periods in history when cardinals were literally walled in, along with a crew of assistants. The Vatican archives and museums have documents referring to payments for some of the additional conclave crews: masters of ceremonies, confessors, sacristans, doctors, nurses and pharmacists.

“It was an entire world,” said Michela Gianfranceschi, a Vatican Museums official.

An official known as a conclave marshal was given the keys to where the cardinals were staying and acted as their intermediary to the outside world while they remained sequestered.

The diaries of past participants suggest that papal conclaves were hardly picnics. Over the centuries there have been fires inside the hall. Fights broke out among cardinals. Riots erupted in the streets outside.

Mary Hollingsworth, in her book about the 1559 conclave, writes that during the four months that led to the election of Pope Pius IV, “the living conditions in the Vatican had deteriorated dramatically: one cardinal died, many were ill (some of them dying subsequently), and the stench in the Sistine Chapel, where 21 of them had their cells, was so bad that the area had to be fumigated.”

The election of Urban VIII took place during three weeks in the summer of 1606, and contemporary documents say that the 55 cardinals involved suffered in the stifling Roman heat. By the time they were released, 12 cardinals had a fever, two had to leave because of illness and others were close to death. Even Urban had to postpone his election ceremony because he was ill.

Some popes sought to find alternative spaces to house the cardinals, including above the colonnade in St. Peter’s Square, a plan that was never carried out, or camping out in the Vatican gardens, which was also nixed, Ms. Gianfranceschi said.

In the early 19th century, four conclaves were held at the Quirinale, the pontifical palace across town that today is the residence of the Italian president. The move to the Quirinale was partly for practical considerations: It was more spacious, and the number of cardinals had grown, Ms. Gianfranceschi said. But the popes lost the palace when Italy became a kingdom, and in 1878 the papal elections were shifted to the Sistine Chapel.

Under John Paul’s rules, a Vatican guesthouse with modest lodgings was built for the voting cardinals.

The average age of the 10 popes elected since the beginning of the 20th century was 67. Only three were in their 70s upon election, including the last two, Benedict XVI and Francis.

When John Paul II was elected, in 1978, he was 58. But his long reign — more than 26 years — prompted cardinals who wanted to avoid another quarter-century pontificate to seek a less spry option. Benedict was selected at 78 and quit at 85, citing a lack of energy, in 2013. Francis was 76, also one of the oldest popes ever elected, though he served 12 mostly vigorous years.

“Someone between 60 and 70 could be the best solution,” said Cardinal Anders Arborelius of Sweden. He acknowledged that the College of Cardinals was made of “elderly gentlemen,” many of whom “looked all the same.”

Among the voting cardinals, age is not a new consideration. In 1878, cardinals elected Leo XIII, who was 67. His poor health and advanced age convinced some cardinals who may have been unsure of his candidacy that his papacy might not last that long.

But Leo XIII lived to be 93.

“We thought we were electing a Holy Father, not an eternal father,” a Vatican joke at the time went.

Now, with access to the best in medical care, a pope in his early 60s could serve 30 years or more. That could hurt the candidacies of Cardinal Pierbattista Pizzaballa of Italy, who is 60, and Cardinal José Tolentino de Mendonça of Portugal, who leads a Vatican office, has deep connections to South America and is a renowned poet, but who is 59.

Voting cardinals themselves cannot be older than 80, after Paul VI introduced the decree of “ingravescentem aetatem,” or advancing age, in 1970.

But one cardinal has gotten younger as the conclave has gotten closer.

Cardinal Philippe Nakellentuba Ouédraogo of Burkina Faso turned 80 on Jan. 25, according to the Vatican yearbook, making him ineligible to vote. But then the Vatican website pushed back his birth date in 1945 to Dec. 31, making him 79 and still a papal elector. The cardinal, who didn’t respond to a request for comment, “has found the secret to stopping time,” Roman newspaper Il Messaggero wrote.

In the 2005 conclave, Cardinal Carlo Martini, a liberal lion, carried a cane he didn’t need in order to make himself a less attractive candidate. Now a cane might give a candidate an edge.

Cardinal Arborelius, 75, and a potential papal candidate himself, said: “I would be too old.”

More than any single issue, the choice of the next pontiff will be dominated by a philosophical question: Who deserves a say in determining the church’s future?