The former archbishop of Buenos Aires, Cardinal Jorge Bergoglio, entered the St. Mary Major basilica through a side entrance just after 8 a.m. (0700 GMT) and left about 30 minutes later. He had told a crowd of some 100,000 people packed in rain-soaked St. Peter's Square just after his election that he intended to pray Friday to the Madonna "that she may watch over all of Rome."
He told cardinals he would also call on retired Pope Benedict XVI on Thursday and celebrate an inaugural Mass in the Sistine Chapel, where cardinals on Wednesday elected him leader of the 1.2 million-strong church in an unusually quick conclave.
Francis, the first Jesuit pope and first non-European since the Middle Ages, decided to call himself Francis after St. Francis of Assisi, the humble friar who dedicated his life to helping the poor.
The new pope immediately charmed the crowd in St. Peter's that roared when his name was announced.
Waving shyly, he told said the cardinals' job was to find a bishop of Rome. "It seems as if my brother cardinals went to find him from the end of the earth, but here we are. Thank you for the welcome."
The 76 year old Bergoglio, said to have finished second when Pope Benedict XVI was elected in 2005, was chosen on just the fifth ballot to replace the first pontiff to resign in 600 years. In the past century, only Benedict, John Paul I in 1978 and Pius XII in 1939 were elected faster.
Francis spoke by phone with Benedict, who has been living at the papal retreat in Castel Gandolfo, and was to visit him on Friday, according to U.S. Cardinal Timothy Dolan. The visit is significant because Benedict's resignation has raised concerns about potential power conflicts emerging from the peculiar situation of having a reigning pope and a retired one.
Benedict's longtime aide, Monsignor Georg Gaenswein, accompanied Francis to the vist at St. Mary Major, the ANSA news agency reported. In addition to being Benedict's secretary, Gaenswein is also the prefect of the papal household and will be arranging the new pope's schedule.
Francis' election elated Latin Americans, who number 40 percent of the world's Catholics but have long been underrepresented in the church leadership. On Wednesday, drivers honked their horns in the streets of Buenos Aires and television announcers screamed with elation at the news.
"It's a huge gift for all of Latin America. We waited 20 centuries. It was worth the wait," said Jose Antonio Cruz, a Franciscan friar at the St. Francis of Assisi church in the colonial Old San Juan district in Puerto Rico. "Everyone from Canada down to Patagonia is going to feel blessed."
The new pontiff brings a common touch. The son of middle-class Italian immigrants, he denied himself the luxuries that previous cardinals in Buenos Aires enjoyed. He lived in a simple apartment, often rode the bus to work, cooked his own meals and regularly visited slums that ring Argentina's capital.
He considers social outreach, rather than doctrinal battles, to be the essential business of the church.
"As a champion of the poor and the most vulnerable among us, he carries forth the message of love and compassion that has inspired the world for more than 2,000 years — that in each other, we see the face of God," President Barack Obama said in a statement.
As the 266th pope, Francis inherits a Catholic church in turmoil, beset by the clerical sex abuse scandal, internal divisions and dwindling numbers in parts of the world where Christianity had been strong for centuries.
While Latin America still boasts the largest bloc of Catholics on a single continent, it has faced competition from aggressive evangelical churches that have chipped away at strongholds like Brazil, where the number of Catholics has dropped from 74 percent of the population in 2000 to 65 percent today.
Francis is sure to bring the church closer to the poverty-wracked region, while also introducing the world to a very different type of pope, whose first words were a simple, "Brothers and sisters, good evening."
He asked for prayers for himself, and for Benedict, whose stunning resignation paved the way for his election.
"I want you to bless me," Francis said in his first appearance from the balcony of St. Peter's Basilica, asking the faithful to bow their heads in silent prayer.
Cardinals elected a new pope to lead the world's 1.2 billion Catholics on Wednesday, overcoming deep divisions to select the 266th pontiff in a remarkably fast conclave.
The 115 cardinals who have locked themselves inside the Sistine Chapel revealed to the world that they have failed to select a new pontiff on their first ballot — a widely expected outcome as the papal conclave got underway Tuesday afternoon.
The cardinals will return for two votes Wednesday morning and, if no white smoke billows over the Vatican, two more votes in the afternoon.
The process will continue until one of the cardinals emerges with a two-thirds majority — 77 votes.
The last nine conclaves have lasted an average of three days.
The puff of black smoke came about three hours after the cardinals locked themselves into the Sistine Chapel to be alone with their thoughts and their prayers as began the selection process for a new Pope.
Once there, the doors will be locked and the participants will have no newspapers, television or, for the social media savvy set, Twitter. They'll get virtually nothing from the outside, other than food.
"It is the way of ensuring that the voice speaking to the cardinals during the conclave belongs to the Holy Spirit and no one else," said ABC News Vatican consultant Father John Wauck.
The ritualistic conclave involves centuries-old customs that have changed very little over time.
The tradition of locking the doors dates back to 1274, when the cardinals met in the remote village of Viterbo.
Two years and eight months into the longest conclave ever, frustrated townspeople tried everything to motivate a quicker decision. They locked the cardinals inside and resorted to more extreme measures, trying to starve them out and tearing the roof off the building to expose them to the elements.
The cardinal electors in the upcoming conclave will be much more comfortable, surrounded by Michelangelo's frescoes in the Sistine Chapel.
A date for the secret event, which literally means "with key," won't be set until the cardinals convene on March 4, a Vatican spokesman said.
Pope Benedict decreed a conclave could be held as soon as all voting cardinals are present. All cardinals under 80 when the papacy is vacated are eligible to participate.
While campaigning is forbidden inside the Sistine Chapel, experts say there is plenty of politicking in the days before.
"This is schmoozing at the highest level," said Christopher Bellitto, a professor at Kean University in New Jersey who has written nine books on the history of the church.
More than half of the cardinal electors were appointed by Benedict, and many are using the days before the conclave to get to know each other and feel out the general sentiment, Bellitto said.
"I think each cardinal has a list of a dozen people in his head. He may know some very well, some by reputation," Bellitto said. "If the cardinals don't know someone, they may ask someone they trust [their opinion]."
On the day the conclave begins, the cardinal electors will attend mass before filing into the Sistine Chapel. For one of the 115, it will likely be his last time wearing a red hat. The cardinal electors have a history of elevating one of their own to the papacy, so that lucky choice will exchange it for the pope's traditional white.
Once inside the Sistine Chapel, the cardinals will take an oath of secrecy and then be given rectangular ballots with the words "Eligo in Summum Pontificem" written on them, meaning, "I elect as supreme pontiff."
Each voting cardinal writes the name of his choice for pope on the ballot and is asked to disguise his handwriting to avoid letting others know who is supporting whom.
Three scrutineers count the ballots, and if no one receives the required two-thirds majority, the votes are burned. A black smoke signal will signal to the world the vote was inconclusive.
Damp straw was once used to turn the smoke black, Bellitto said, however after years of confusion, dye has reportedly been used.
There can be a maximum of four ballots in a single day, and if after three days the cardinals still haven't selected a pope, the voting sessions can be suspended for a day of prayer and discussion.
Throughout the secret process, the cardinals will eat and sleep in a private guest house on the edge of Vatican City.
Only a select staff of doctors, cooks and housekeepers, all sworn to secrecy, are allowed to interact with the cardinals.
For approximately half of the cardinal electors, this will be their second time participating in the mystical event.
Cardinal William Levada of San Francisco, a first-timer, said his colleagues in the college of cardinals have given him an idea of what to expect.
"I think it is a prayerful atmosphere," he said. "No campaigning. It is forbidden to campaign there. You can't put yourself forward."
Habemus Papem: We Have A Pope!
The first sign that the 1.2 billion Catholics worldwide have a pope will come when white smoke curls out of the Sistine Chapel's chimney.
Inside the chapel, the man who is chosen to be pope will be asked by the cardinal dean if he accepts. If so, he will be asked for his papal name.
"Generally, the way it works is there is some level of affection toward a certain name," Bellitto said.
At his first general audience as pope, Benedict XVI said he chose the name to "create a spirutual bond with Benedict XV, who steered the church through the period of turmoil caused by the First World War," and also cited his fondness for the Benedictine Order as an influence.
The newly elected pontiff wiill be fitted with the papal vestments before making his way to St. Peter's Basilica, his identity still unknown to the world.
French Cardinal Jean-Louis Tauran, the senior cardinal in the order of the deacons, will step onto the balcony of St. Peter's Basilica to tell the world the name of the man chosen as the next pontiff.
Tauran is expected to make the announcement unless he is chosen pope, in which case another cardinal would deliver the news.
The new pope will then step onto the balcony and greet the world for the first time.
However, the secrets of the conclave that elevated him to the position will be forever be kept among one of the world's most exclusive clubs.
By DAVID WRIGHT (@abcdavid) and ALYSSA NEWCOMB (@alyssanewcomb) March 11, 2013
The Vatican press office said the decision was taken during a vote today of the College of Cardinals. Tuesday will begin with a Mass in the morning, followed by the first balloting in the afternoon.
Only a handful of popes have ever done so.
The last was Pope Gregory XII, who stepped down in 1415 in a deal to end the Great Western Schism, a dispute among competing papal claimants. The most famous resignation was Pope Celestine V in 1294; Dante placed him in hell for it.
Benedict is saying farewell this morning to his closest advisers in Clementine Hall at the Apostolic Palace. Then shortly before 5 p.m., he will leave the palace for the last time as pope and fly by helicopter to the papal retreat at Castel Gandolfo, south of Rome.
Benedict Greets Cardinals on Last Day As Pope
Exactly at 8 p.m. — when his resignation takes effect — the doors at Castel Gandolfo will close and the papacy that began on April 19, 2005, will come to an end.
Tens of thousands of people toting banners saying "Grazie!" - "thank you" - jammed the piazza to bid farewell to the pope at his final general audience - the appointment he has kept each week to teach the world about the Catholic faith.
Pilgrims and curiosity-seekers picked spots along the main boulevard leading to the square to watch Wednesday's event on giant TV screens. Some 50,000 tickets were requested for Benedict's final master class, but Italian media estimated the number of people actually attending could be double that.
"It's difficult - the emotion is so big," said Jan Marie, a 53 year old Roman in his first years as a seminarian. "We came to support the pope's decision."
With chants of "Benedetto" erupting every so often, the mood was far more buoyant than during the pope's final Sunday blessing and recalled the jubilant turnouts that often accompanied him at World Youth Days and events involving his predecessor, Pope John Paul II.
Benedict on Thursday will become the first pope in 600 years to resign, a decision he said he took after realizing that, at 85, he simply didn't have the strength of mind or body to carry on. He will meet Thursday morning with cardinals for a final time, then fly by helicopter to the papal residence at Castel Gandolfo south of Rome.
There, at 8 p.m., the doors of the palazzo will close and the Swiss Guards in attendance will go off duty, their service protecting the head of the Catholic Church over - for now.
Many of the cardinals who will choose Benedict's successor were in St. Peter's Square for his final audience, including retired Los Angeles Cardinal Roger Mahony, object of a grass-roots campaign in the U.S. to persuade him to recuse himself for having covered up for sexually abusive priests. Mahony has said he will vote.
Vatican officials say cardinals will begin meeting on Monday to decide when to set the date for the conclave to elect the next pope.
But the rank-and-file in the crowd on Wednesday weren't so concerned with the future; they wanted to savor the final moments with the pope they have known for eight years.
"I came to thank him for the testimony that he has given the church," said Maria Cristina Chiarini, a 52 year old homemaker who traveled by train early Wednesday from Lugo, near Ravenna, with some 60 members of her parish. "There's nostalgia, human nostalgia, but also comfort, because as a Christian we have hope. The Lord won't leave us without a guide."
Benedict received a lengthy standing ovation when he entered the packed audience hall Wednesday. He was interrupted by applause by the throngs of people, many of whom had tears in their eyes.
At the start of his audience, he repeated in Italian what he had told cardinals Monday in Latin: that he simply didn't have the strength to continue. He said "I did this in full liberty for the good of the church."
He asked the faithful "to continue to pray for the pope and the church."
There is talk that an American could be next in line for the papal office now that Pope Benedict the sixteenth is stepping down from his office at the end of the month. He is the first Pope to resign in 600 years.
Monday morning, Ballwin, Missouri native and New York Cardinal Timothy Dolan reflected on the possibility that he could be moving to Rome sometime soon. Dolan says, "Well it's awesome, you're right. I really .. I mean theoretically I've known that since I was made a cardinal last year that that would be one of the awesome responsibilities, but it's not something you think about. I don't have any insider information, but I would presume that his esteem for the office as the successor of Saint Peter and the chief pastor of the church universal ... that esteem is so high that in all humility he simply said, I can't do it anymore."
Cardinal Dolan. along with Cardinal Raymond Burke, the former archbishop of the St. Louis Archdiocese are two of seven Americans in the College of Cardinals who can vote for the next pope . Dolan says he believes 85-year-old Pope Benedic's health is not the best, "He knows he's getting a little wobbly. When he was elected as successor of St. Peter in 2005, he shrugged and said to his fellow cardinals, boy, I sure don't have the strength and the durability that blessed John Paul the Second had. So he's been well aware of his frailty."
Church insiders say Italian cardinals are more likely to succeed. The pope's resignation sets the stage for a conclave to elect a new pope before the end of March.