Pope Leo XIV will be the Catholic Church's 267th leader.
VATICAN CITY -- The temporary chimney atop the Sistine Chapel released a plume of white smoke on Thursday evening local time, signaling that the 133 cardinals working inside had reached a two-thirds majority to elect a new pope for the Catholic Church.
American Cardinal Robert Prevost was shortly thereafter announced as the 267th pontiff. He chose the name Leo XIV, a senior cardinal deacon announced.
The 69-year-old Chicago native is the first American pope and is seen as a diplomat in the church.
"This is the first greeting of the risen Christ. May the peace be with you," Leo said in Italian in his first remarks as pope. "This is the peace of the risen Christ."
(The Associated Press and ABC News contributed to this report.)
Pope Leo XIV - history-making, the first American Pope. Now, David Muir reports from the Vatican in the breaking, new "20/20" special edition. Watch the premiere of "The American Pope | Leo XIV" tonight at 9/8c on ABC. Stream on Hulu and Disney+
The official start of the papal conclave to elect the next leader of the Catholic Church is about to begin.
The 133 voting cardinals are expected to take their oaths at the Sistine Chapel at about 4:30 p.m. following a procession from the Pauline Chapel in reverse seniority.
The master of ceremony will then oversee the official start of the conclave at 5 p.m.
Cardinal Timothy Dolan, the archbishop of New York, said in a post to X on Wednesday that he and the other North American cardinals will bring the "intentions" of regional Catholics to the conclave.
"Please keep us in your prayers," Dolan wrote.
The Conclave is now underway, at least, in ceremony.
Mass marking the start of the process came to a close Wednesday in the Vatican and hundreds of people poured into St. Peter's Square.
The Vatican released video of cardinals, 220 of them, processing down the main aisle inside St. Peter's Basilica.
This Mass, in particular, was meant to pray for the 133 voting cardinals who will be choosing the next pope. The dean of the College of Cardinals asked for prayers for the cardinals as they take on this weighty decision.
The Vatican estimates roughly 250,000 people have made the pilgrimage here to Rome to witness the experience of the Conclave in what way they can from the outside.
An American priest flew in to pray for the cardinals.
"Well the prayers and the scripture readings were such that, basically, inviting the Holy Spirit to be present and to be with the cardinals as they prepared to gather in the Sistine Chapel in just a little while and pray that the Holy Spirit helps them to choose a successor to St. Peter," Father Bill Champlin said.
Father Thomas Reese, senior religious analyst for the Religious News Service, shared about what he believes cardinals will be considering.
"I think is looking for three things in a candidate. First, does this man agree with me on the issues facing the church and the direction the church should go in. Secondly, is this somebody I have a good relationship with, because, you know, after he becomes pope, I want to be able to talk to him. I want to listen to me. I want to have influence in this next papacy, And then thirdly, he is going to look for someone who will go over well in my part of the world."
Cardinals will now take the oath of secrecy late Wednesday afternoon before they're locked in the Sistine Chapel. They will take just one round of votes Wednesday around 5 p.m. Rome time, so the first smoke signals from the Sistine Chapel will come sometime in the evening.
Of all the ceremonies associated with electing a new pope, the one most familiar to the general public is the smoke that emanates from a stovepipe chimney atop the Sistine Chapel after every round of balloting.
Black smoke -- fumata nera in Italian -- indicates an inconclusive vote, while white smoke -- fumata bianca -- will signify that a new pope has been elected. Along with the white smoke, the bells of St. Peter's Basilica will ring to proclaim the event to the world.
The ceremonial smoke is not created by the burning of the ballots. The voting slips are burned in a stove that dates back to the 1922 conclave and is set up for the occasion in the Sistine Chapel.
The smoke that wafts from the stovepipe chimney is created using chemical pellets that are burned in another stove that's connected to the chimney, which is temporarily erected atop the Sistine Chapel just for that purpose.
Assuming the elected cardinal accepts the office, the new pope's identity is typically revealed within an hour of the final ballot, after he chooses the name by which he will be known as pope.
The new pope then emerges onto the balcony to present himself to the world and deliver his first blessing to the crowd gathered below in St. Peter's Square.
-ABC News' Christopher Watson
