Cardinals began election of a new Pope on Tuesday, with a special Mass in St Peter’s Basilica, as 1.2 billion Catholics wait to know who takes over as head of the Roman Catholic Church.
The 115 cardinal-electors, after the Mass went into the Sistine Chapel to begin their secret deliberations.
They will vote four times daily until two-thirds can agree on a candidate.
Before the election began, a report had it that anti-mafia investigators had carried out a string of raids in the diocese of the leading candidate, just as the cardinals had been urged to overcome divisions at a special mass ahead of the papal conclave.
In a homily before thousands of pilgrims and the most senior figures in the church, Angelo Sodano, the dean of the college of cardinals, made a last-ditch attempt to banish infighting, as he extolled the virtues of unity amid diversity.
But even as preparations for the mass were being made, Cardinal Angelo Scola, the archbishop of Milan – and reportedly the hot favourite to be the next pope – suffered a swingeing blow.
Anti-mafia detectives swooped on homes, offices, clinics and hospitals in Lombardy, the region around Milan, and elsewhere.
A statement said the dawn raids were part of an investigation into “corruption linked to tenders by, and supplies to, hospitals”.
Pope Benedict XVI’s resignation and the recent damage to the Church’s reputation make the choice of the cardinal-electors especially hard to predict, the BBC’s James Robbins in Rome said.
They will weigh pressure for a powerful manager to reform the Vatican against calls for a new Pope able to inspire the faithful, our correspondent adds.
At Tuesday morning’s “Mass for the Election of the Supreme Pontiff” in St Peter’s Basilica, the cardinals sought divine guidance for the election ahead.
In his homily, the Dean of the College of Cardinals, Cardinal, Angelo Sodano praised the “brilliant pontificate” of Pope Benedict and implored God to grant another “Good Shepherd” to lead the church.
He outlined the mission Catholics believe was given by Jesus Christ to St Peter, the first Pope, emphasising love and sacrifice, evangelisation and the unity of the church.
The BBC’s Michael Hirst in Rome said the speech was more measured in tone than the address given in 2005 by Cardinal Joseph Ratzinger before he became Pope Benedict, which featured a fiery attack on the “dictatorship of relativism.”
After the 115 cardinal-electors took an oath of secrecy, Msgr Guido Marini, papal master of ceremonies, will call out the words “Extra omnes” - “Everybody out” - and the chapel doors will be locked to outsiders.