A new pope

After Pope Benedict XVI's surprise resignation, Cardinal Jorge Mario Bergoglio of Argentina was elected, and will lead the Roman Catholic Church as Pope Francis.

At installation Mass, pope urges protection of the weak

Pope Francis officially began his ministry by speaking of the need to protect “the poorest, the weakest, the least important.”

Pope Francis waved to the fervent crowd as he arrived to his installation Mass in St. Peter's Square.

AP Photo/Michael Sohn

Pope Francis waved to the fervent crowd as he arrived to his installation Mass in St. Peter's Square.

Pope Francis took part in his inaugural Mass in St. Peter's Square on Tuesday.

ALESSANDRO BIANCHI/REUTERS

Francis took part in his inaugural Mass in St. Peter's Square on Tuesday.

Among the hundreds of dignitaries in attendance was Vice President Joe Biden.

AP Photo/Riccardo De Luca

Among the hundreds of dignitaries in attendance was Vice President Joe Biden.

The fisherman's ring was placed on the finger of Pope Francis by Cardinal Angelo Sodano, dean of the College of Cardinals.

STEFANO RELLANDINI/REUTERS

The fisherman's ring was placed on the finger of Pope Francis by Cardinal Angelo Sodano, dean of the College of Cardinals.

Nuns listened as Pope Francis read the gospel.

Gregorio Borgia/AP

Nuns listened as Pope Francis read the gospel.

Cardinals attended Pope Francis' inaugural Mass.

Andrew Medichini/AP

Cardinals attended Pope Francis's inaugural Mass.

During his inaugural Mass, Francis was interrupted by applause several times.

AP Photo/Gregorio Borgi

During his inaugural Mass, Francis was interrupted by applause several times.

Priests lined up in St. Peter's Square.

Andrew Medichini/AP

Priests lined up in St. Peter's Square.

Hundreds of thousands packed St. Peter's Square for the pope's installation Mass.

Jeff J Mitchell/Getty Images

Hundreds of thousands packed St. Peter's Square for the pope's installation Mass.

A priest delivered communion to the faithful in St. Peter's Square.

AP Photo/Michael Sohn

A priest delivered communion to the faithful in St. Peter's Square.

German Chancellor Angela Merkel attended the installation of the new pope.

AP Photo/Riccardo De Luca

German Chancellor Angela Merkel attended the installation of the new pope.

French Prime Minister Jean-Marc Ayrault was among the world leaders who attended the Mass.

AP Photo/Dmitry Lovetsky

French Prime Minister Jean-Marc Ayrault was among the world leaders who attended the Mass.

Zimbabwe's President Robert Mugabe and his wife Grace attended the Mass.

Stefano Rellandini/REUTERS

Zimbabwe's President Robert Mugabe and his wife Grace attended the Mass.

Spain's Prince Felipe (left) and Princess Letizia, and Spain's Prime Minister Mariano Rajoy (right) were in attendance.

Paul Hanna/REUTERS

Spain's Prince Felipe (left) and Princess Letizia, and Spain's Prime Minister Mariano Rajoy (right) were in attendance.

Pope Francis waved to the crowd from an open-air vehicle.

EPA/ETTORE FERRARI

Pope Francis waved to the crowd from an open-air vehicle.

Pope Francis arrived to his installation Mass.

Gregorio Borgia/AP

Pope Francis arrived to his installation Mass.

Pope Francis got out of his vehicle to bless a disabled man prior to the Mass.

Dmitry Lovetsky/AP

Pope Francis got out of his vehicle to bless a disabled man prior to the Mass.

Many of the faithful took photos of Francis as he made his way through St. Peter's Square.

Christopher Furlong/Getty Images

Many of the faithful took photos of Francis as he made his way through St. Peter's Square.

Pope Francis reached for a child during his tour through St. Peter's Square at the Vatican.

AP Photo/Riccardo De Luca

Pope Francis reached for a child during his tour through St. Peter's Square at the Vatican.

Argentines watched the inaugural Mass on a giant screen next to the Metropolitan Cathedral in Buenos Aires.

ENRIQUE MARCARIAN/REUTERS

Argentines watched the inaugural Mass on a giant screen next to the Metropolitan Cathedral in Buenos Aires.

A woman held a sign as she watched the installation from Buenos Aires.

AP/Natacha Pisarenko

A woman held a sign as she watched the installation from Buenos Aires.

Faithful carried a Vatican flag as they waited to watch a broadcast of the inaugural mass in Buenos Aires.

ENRIQUE MARCARIAN/REUTERS

Faithful carried a Vatican flag as they waited to watch a broadcast of the inaugural Mass in Buenos Aires.

Argentina's President Cristina Fernandez  de Kirchner, left, greeted Dutch Prince Willem-Alexander.

AP Photo/Gregorio Borgia

Argentina's President Cristina Fernandez de Kirchner, left, greeted Dutch Prince Willem-Alexander.

Chalices containing hosts were prepared before the Mass.

ALESSANDRO BIANCHI/REUTERS

Chalices containing hosts were prepared before the Mass.

Nuns ran through St. Peter's Square to get a good vantage point.

REUTERS/Max Rossi

Nuns ran through St. Peter's Square to get a good vantage point.

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//c.o0bg.com/rf/image_90x90/Boston/2011-2020/2013/03/19/BostonGlobe.com/Foreign/Images/036310202-701.jpg The papal inauguration

Inside the installation Mass in St. Peter’s Square, where hundreds of thousands of people were expected to attend.

Current status

Argentine Cardinal Jorge Bergoglio, a Jesuit, was elected pope, making him the first pontiff from the Americas.

How a new pope is elected

Only cardinals under age 80 are eligible to vote.

• All 115 Cardinals take an oath of secrecy about the election.

Any baptized Roman Catholic male is eligible for election as pope.

• Once conclave begins, the cardinals are sequestered within Vatican City.

• A two-thirds majority is required to elect a new pope.

Two ballots are held each morning and two each afternoon in the Sistine Chapel.

The ballots are burned after each round of voting.

Black smoke from the chimney above the Sistine Chapel means no decision.

White smoke signals that cardinals have chosen pope and he has accepted.

The new pope is introduced from the loggia overlooking St. Peter’s Square with the words "Habemus Papam!" (Latin for "We have a pope!") and he then imparts his first blessing.