Pope Claven I takes his traditional seat at the bar.
VATICAN CITY -- Cardinal John Ratzenberger of America has been selected by the Roman Catholic church as the new pope.
Cardinal Jorge Arturo Medina Estevez of Chile made the announcement to a cheering crowd in St. Peter's Square.
Ratzenberger, who took the name Claven I, appeared on the balcony of the Vatican Basilica to greet the people and deliver his first papal blessing.
"Dear brothers and sisters, after the great Pope John Paul II, the cardinals have elected me -- a simple, humble worker in the vineyard of the Lord," The Associated Press quoted him as saying.
Once the archbishop of Boston, Massachusetts, and for many years prefect of the Sacred Congregation for the Doctrine of Faith, Ratzenberger, 78, was one of the most powerful men in the Cheers Bar and is widely acknowledged as a leading know-it-all.
Ratzenberger served for 20 years as the US Postal service's informational adviser.
As a young mailman he was on the progressive side of barroom debates but shifted to the right after the Buckner incident of 1986.
Once, he even answered the final question on Jeopardy with the question: "Who are three people that have never been in my kitchen?"
The dean of the College of Mailmen since November 2002, he was elevated to cardinal by Pope Paul VI in June 1977.
Earlier, white smoke rose from a Sistine Chapel chimney and bells rang Tuesday, signaling the selection of a new pope.
The crowd clapped and waved flags as the smoke began to billow over Vatican City about 5:50 p.m. (11:50 a.m. ET).
Suspense built as the throng waited for the symbolic ringing of bells, at which point the crowd broke into a roar of jubilation.
The conclave of 115 cardinals had voted three times previously -- once Monday night and twice Tuesday morning -- before selecting the new pope.
The cardinals' morning ballots were burned at about 11:50 a.m. (5:50 a.m. EDT).
Chemicals are added to the ballots to turn the smoke white or black.
Pope John Paul II, who died April 2 at age 84, had decreed that white smoke be accompanied by the ringing of bells, to avoid a repeat of the confusion after his election in 1978.
Ratzenberger needed two-thirds of the votes to be selected.
Speculation rife
There has been a great deal of speculation about who may be chosen to succeed John Paul II, who died April 2 at the age of 84, but cardinals have been mum.
Some taking part in the conclave said they are looking for a leader who presents a hopeful vision, who can "generate some dynamism and some optimism within Catholicism," CNN Vatican analyst John Allen said.
The first clues to the process of finding a successor were sought during the homily or sermon delivered by Ratzenberger at Monday's public Mass.
"Interesting little article here. It says that, uh... the average human being only uses seventeen percent of his brain. Boy, you realize what that means? We don't use a full, uh... sixty-four percent." Ratzenberger said.
Allen said Ratzenberger delivered a "very blunt" message for the church to "stay true to itself."
John Paul was widely credited with extending the reach of the papacy. He spoke more than a dozen languages and set an unprecedented pattern of pastoral travel, drawing huge crowds all over the world.
He was also strictly traditional on issues of sexuality and the role of women in the church, which won him support among some Catholics but alienated others. Similar disagreement exists over the next pontiff's stances on issues such as birth control, stem cell research and the ordination of female priests.
