Argentina's Jorge Mario Bergoglio was elected Pope Francis I on Wednesday, becoming the first Latin American pontiff in a surprise decision that signalled a desire for a more open Catholic Church.
The 76-year-old moderate emerged smiling on to the balcony of St Peter's Basilica to cries of "Long live the pope!" as tens of thousands of pilgrims cheered, cried and applauded.
The first non-European pope in more than 1,200 years of Church history, Francis called for "brotherhood" among the world's 1.2 billion Catholics and prayed the Hail Mary together with the crowd in St Peter's Square.
He said he felt as if the cardinals that elected him had gone to "the other end of the world" to find him -- and across the Atlantic Ocean in Buenos Aires celebrations erupted.
World leaders hailed the election of a pope who chose to name himself after St Francis, with US President Barack Obama hailing "a champion of the poor and the most vulnerable among us."
Argentinian President Cristina Kirchner wished her fellow countryman "a fruitful pastoral mission."
Justin Welby, the new leader of the world's Anglicans, said in a message to Francis that he was looking forward to "walking and working together to build on the consistent legacy of our predecessors."
Vatican spokesman Federico Lombardi said the choice by 115 cardinals in the Sistine Chapel had "widened the perspective of the Church" and he hailed their boldness in "crossing the Ocean."
Sergio Rubin, religious writer for the Buenos Aires newspaper Clarin, said that, like Pope John Paul II, Bergoglio was "conservative at the level of doctrine, and progressive on social issues."
The election was also being seen as a recognition of a thriving faith in Latin America, which has the highest number of Catholics in the world -- in contrast to the decline of Catholicism in its traditional bastion in Europe.
Francis also publicly thanked his 85-year-old predecessor Benedict XVI, who shocked the world last month by becoming the first pope to resign for seven centuries.
The papal Twitter account @pontifex announced the election with a simple phrase in Latin: "Habemus Papam Franciscum" ("We Have Pope Francis").
There had been growing calls both within and outside the Church for a new pope to be chosen from the southern hemisphere for the first time but Bergoglio was never considered one of the frontrunners.
"I can't believe it! An Argentinian pope!" said Silvia Pastormerlo, a 50-year-old from Argentina in St Peter's Square.
-- Happy and proud --
Also in the crowd was Julio Cesar Attaremo, a 42-year-old notary from Santa Fe, in Argentina. "We're very happy and proud, not just for Argentina but for the whole of South America," he said.
"Bergoglio has character. He's very humble and he's someone who really goes out to the people."
The new pope is believed to have been the runner-up at the conclave in 2005 that elected Benedict -- although cardinals taking part are sworn to secrecy on pain of excommunication.
The Vatican said his formal inauguration mass would be on Tuesday -- an important date in the Catholic calendar because it is the Feast of St Joseph, patron saint of the universal Church.
White smoke earlier billowed from the chimney on the Sistine Chapel and the bells of St Peter's Basilica rang out, signalling the election had taken place after five rounds of voting -- one more than when Benedict was elected.
Bergoglio is the first Jesuit to become pope.
The Argentinian railworker's son of Italian descent, the 266th pope in the Catholic Church's 2,000-year history, retired to a chamber known as the "Room of Tears" after the nomination to don his white papal vestments and then prayed in the Pauline Chapel.
Bells pealed in churches across Italy to celebrate the announcement and residents of Rome raced to the floodlit 17th-century Vatican square.
Cardinals had been locked up behind the Vatican walls and cut off from the outside world since Tuesday to make their choice.
Benedict's eight-year papacy was riven by scandals and the new pope will face immediate challenges -- principally stamping his authority on the Vatican machinery and trying to bring back a Catholic flock that is deserting churches across the West.
The scandal of hushed-up sexual abuses of children by paedophile priests going back decades has also cast its shadow over the conclave.
Benedict's style was often seen as too academic and he was never as popular as his predecessor Pope John Paul II. Many of the cardinals have called for the new pope to be a better communicator, able to reach out particularly to young people.
Conclaves are usually only held after a pope dies and are sometimes decades apart -- the last one was in 2005, the one before that 1978.
But Benedict broke with tradition, becoming the first pontiff to step down since the Middle Ages. The German has said he will retire to a former nunnery inside the Vatican -- creating a delicate situation for the Church.
The Vatican said Francis had already called his predecessor and would meet with him soon.
In one of his last acts as pope, Benedict issued a decree allowing cardinals to bring forward the date of a conclave in the event of a pope's resignation -- a move seen by many as potentially setting a precedent for ageing pontiffs in the future.
Vatican experts said the prospect of future resignations could have encouraged the cardinals to elect an older candidate.
An elated Claudio Bonani, 42, in a crowd of worshippers at the cathedral in Buenos Aires -- Bergoglio's birthplace -- said the choice heralded the beginning of a "great papacy".
"He is a simple man, and he has a lot of compassion for the neediest," Bonani said.