News In Depth
No clear front-runner for pope
No clear front-runner has emerged as a successor to Pope Benedict XVI who is formally resigning as leader of the Roman Catholic Church.
Cardinals across the globe are arriving in Rome in advance of the conclave, when those eligible to vote are literally locked away to cast ballots in secret in the Vatican's Sistine Chapel.
Before the conclave starts, cardinals are expected to take part in general congregations, pre-conclave meetings where they discuss the qualities needed in a future pope.
Speculation is mounting that the cardinals could choose to back a candidate from the developing world - either Africa, Latin America, or Asia - which have the largest Catholic populations.
But it is unclear whether a cardinal from any of these continents would be able to command the necessary majority.
By country, Italian cardinals make up the biggest group of electors, at 28 votes and by continent, Europe is dominant with 62 electors.
There has not been an Italian pope since John Paul I died in 1978 and some commentators believe that the papacy could well revert back after the reigns of John Paul II, a Pole, and Pope Benedict, who is German-born.
Michael Walsh, a Vatican expert and historian who revised the latest edition of the Oxford Dictionary of Popes, said he believed the papacy could return to an Italian.
He said Pope Benedict's choice of Cardinal Gianfranco Ravasi to lead the Vatican's Lenten spiritual retreat this year was "significant" as this was viewed as a papal favour.
Cardinal Karol Wojtyla was chosen for this task before going on to become Pope John Paul II, he said.
"Clearly there is a lot of pressure from around the church for somebody from Africa or Latin America," he said.
"The question is - who is it going to be?
"The only names being regularly mentioned are Cardinal Peter Turkson from Ghana and Cardinal Odilo Scherer from Brazil.
"I think what they may very well do is go back to an Italian.
"The Italians are a very large contingent.
"They are more likely than most to operate as a bloc, because they know one another.
"Most of the 28 are cardinals in the curia (the Vatican departments which govern the global Church) and they know one another."
Mr Walsh said he backed a return to a more collegial style of governing the Church with less power centralised in the hands of the curia.
"I believe there ought to be an Italian pope because I believe we ought to cut down on the power of the Vatican," he said.
"It ought to return to being a Bishop of Rome and if there is a return to the Bishop of Rome then it ought to be an Italian."
Mr Walsh said his personal favourite to become Pope would be Cardinal Luis Tagle, Archbishop of Manila since 2011 but he did not think he would be elected.
"He has been a great success in Manila, he is very approachable and very well liked by everybody.
"He won't get it for one very good reason which is simply that he is too young, at 55-years-old, he could be pope for 30 years, which is an awfully long time," he said.