San Francisco Frontiers - Leo XIV celebrates first mass as pope in Sistine Chapel

Chicago-born Robert Francis Prevost on Thursday became the 267th pope, spiritual head of the world's 1.4 billion Catholics and successor to Argentina's Pope Francis, after a secret conclave by his fellow cardinals in the Vatican's Sistine Chapel.

"The American pope," blazed headlines from the front pages of Italy's newspapers Friday after the announcement from the balcony of St Peter's Basilica introducing the modest, soft-spoken former missionary to the world.

The 69-year-old, sometimes referred to in Rome as the "Latin Yankee" for his decades-long missions in Peru, returned Friday to the Sistine Chapel to preside over a private mass with cardinals, broadcast by the Vatican.

Leo entered the chapel in a white papal robe trimmed in gold, carrying a ferula, or cross-topped staff, stopping occasionally to greet cardinals before commencing the mass.

A day after his election, signalled by white smoke billowing from the chimney of the Sistine Chapel, many were still digesting the choice by the conclave's 133 voting cardinals.

"A pope from the United States is almost more surprising than an Argentine and Jesuit pope," such as Francis, wrote the Italian newspaper Corriere della Sera on Friday. Francis was the first pope ever named from the Americas.

- Missionary in Peru -

The Vatican released video images of the moments after Leo's secret election on Thursday, showing him praying at a chapel altar and shaking hands and receiving congratulations in a sea of scarlet-robed cardinals.

Tens of thousands of well-wishers cheered Leo for his first appearance at the balcony of St Peter's Basilica on Thursday evening -- despite many having no idea who the man before them was.

The American, a member of the Augustinian order who spent two decades in Peru and was only made a cardinal in 2023, had been on many Vatican watchers' lists of potential popes, although he is far from being a globally recognised figure.

Over the coming days, from Friday's mass in the Sistine Chapel to Sunday's midday Regina Coeli prayer and a meeting with journalists at the Vatican on Monday, his actions and words will be closely scrutinised.

Across the globe in Peru, well-wishers including the bishop of El Callao outside Lima, Luis Alberto Barrera, saluted the Augustinian's engagement in the Andean country.

"He showed his closeness and simplicity with the people," Barrera told AFP.

"He was a very simple person who adapted to everything, like any good missionary."

In Chicago, locals celebrated his love of baseball, deep-dish pizza and his working-class South Side neighbourhood in the United States' third-largest city.

The Chicago Tribune called him "the pride and joy of every priest and nun" at his local parish, where he went to school and served as an altar boy, while a debate erupted over which of the city's rival baseball teams Leo supported: the White Sox, his brother ultimately confirmed.

- Build bridges -

In his first speech to the crowds packed into St Peter's Square Thursday, Leo echoed his predecessor Francis with a call for peace.

"Help us, and each other, to build bridges through dialogue, through encounter, to come together as one people, always in peace," he said.

"We must seek together how to be a missionary Church, a Church that builds bridges, which holds dialogues, which is always open."

World leaders raced to welcome his election and promised to work with the Church on global issues at a time of great geopolitical uncertainty.

Leo faces a momentous task. As well as asserting his moral voice on a conflict-torn world stage, he must try to unite a divided Church and tackle burning issues such as the continued fallout from the clerical sexual abuse scandal.

As Cardinal Prevost, the new pope defended workers and the poor and reposted articles online critical of US President Donald Trump's anti-migrant policies.

But Trump nevertheless welcomed his election, saying on Thursday it was a "great honour" to have a pope from the United States.

It was not known how many ballots it took to elect Leo XIV, but the conclave followed those of recent history, wrapping up in less than two days.

- Consensus candidate -

The crowds erupted with cheers when white smoke billowed into the sky from the Sistine Chapel chimney, the traditional sign that a new pope has been elected.

"I'm not an overly religious person but, being here with all these people just blew me away," said 39-year-old Joseph Brian from Belfast in Northern Ireland.

With the choice of Prevost, experts said, the cardinals had opted for continuity with the late Francis, a progressive who shook up the Church in his 12-year papacy.

"He (Leo) is a moderate consensus candidate who fits into a soft continuity, a gentle continuity with Pope Francis, who will not alienate conservatives," said Francois Mabille, a researcher at the Paris-based think tank IRIS and author of a book on Vatican strategy.

"At least, he has not alienated them" so far.

Vatican watchers agreed that Prevost's more soft-spoken style should help him as he faces turbulent times on the international stage, acting as a counterpoint to more divisive voices.

Italian cardinal Gianfranco Ravasi told the Corriere della Sera that Leo was "a very simple person, intensely kind. He is in the vein of Francis, but less spiky".

A.Smith--SFF