Final adjustments are being made to the Sistine Chapel today before the 115 Roman Catholic cardinals enter for the conclave to choose the next pope.
Once there, the doors will be locked Tuesday 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. Technicians have already installed cellphone-jamming devices to keep the outside world unaware of what the cardinals speak about.
"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," the Rev. John Wauck, ABC News Vatican consultant, said.
Workers hung red drapes this morning over the window at St. Peter's Basilica, where the world will see the new pope for the first time once he's elected after the conclave.
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The ritualistic conclave involves centuries-old customs that have changed very little over time.
The tradition of locking the doors dates back from 1268-1271, 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.
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 used 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 Tuesday, 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.
"When you go with your ballot paper in your hand and hold it up in front of the alter and say, 'I call on the Lord Jesus who will be my judge to witness that I am voting for the one I believe to be worthy' - that's really a moment of intense emotion," said Cardinal Wilfrid Napier, Archbishop of Durban, South Africa.
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."