VATICAN CITY, – The historic conclave to choose a successor for the first pope to resign in over 700 years begins on Tuesday, with the world in suspense over a secret election with no clear frontrunner.
The 115 cardinal electors who will choose the next leader of the world's 1.2 billion Catholics move into a residence inside the Vatican walls where they will sleep and eat for the duration of a conclave expected to last no more than a few days.
The cardinals will be completely cut off – banned from any communication with the outside world and bound by a strict oath of secrecy on pain of excommunication – until they have chosen one in their midst to be pope.
The prayers will begin with a special mass called "For the Election of the Roman Pontiff" in St Peter's Basilica starting at 0900 GMT.
Cardinals will later file into the Sistine Chapel from 1530 GMT chanting in procession to invoke the Holy Spirit to inspire their choice.
The cardinals are set to hold a first round of voting later on Tuesday – but the Vatican has already said it expects the smoke from the burning of the ballots to be black indicating no papal election has taken place.
Ballots on subsequent days will be burnt at around 1100 GMT after two rounds of voting in the morning and at around 1800 GMT after two rounds in the afternoon – the smoke is famously turned white if there is a new pope.
Among the possible candidates, three have emerged as clear frontrunners – Italy's Angelo Scola, Brazil's Odilo Scherer and Canada's Marc Ouellet, all of them conservatives cast in the same mould as "pope emeritus" Benedict XVI.
But the rumour mill in the Vatican has thrown up many more names in recent days including cardinals from Austria, Hungary, Mexico, the Philippines, South Africa and the United States – including inspiring pastors and communicators.
The field is wide open but a few key aims unite many of the cardinals after Benedict's troubled eight-year papacy – reform the intrigue-filled Vatican bureaucracy, counter rising secularism in the West and find new inspiration for Catholics.
The scandal over decades of sexual abuse of children by paedophile priests – and the efforts made by senior prelates to cover up the crimes – has cast a long shadow over the Church that will be an urgent task for any new pope.
There have been calls from within the Church too for a rethink of some basic tenets such as priestly celibacy, the uniform ban on artificial contraception and even allowing women to be priests as in other Christian denominations.
The tradition of holding conclaves goes back to the 13th century when cardinals were locked into the papal palace in Viterbo near Rome by the angry faithful because they were taking too long to make their decision.
That conclave still dragged on for nearly three years but the rules have been reworked since then and the longest conclave in the past century – in 1922 – lasted only five days. Benedict's election took just two days.
Benedict stunned the world on February 11, announcing that he no longer had the strength of body and mind to keep up with a fast-changing modern world shaken by vital questions for the Roman Catholic Church.
In a series of emotional farewells, 85-year-old Benedict said he would live "hidden from the world" and wanted only to be "a simple pilgrim" on life's last journey.
Vatican experts have said the German's decision, which makes him only the second pope to resign by choice in the Church's 2,000-year history, could mean future popes will also step down once their strengths begin to fail them. Cardinals prayed for divine guidance at their last Sunday masses before the conclave in churches across Rome.
Top 10 favourites
Only a few of the 115 cardinal electors taking part in the conclave starting on Tuesday are considered pontiff material, or "papabile".
Here are some of the top contenders to become the next head of the world's 1.2 billion Catholics, as cardinals gather in the Sistine Chapel:
ANGELO SCOLA: The 71-year-old archbishop of Milan is a keen promoter of inter-religious dialogue, particularly between Muslims and Christians. He is also an expert on bioethics, an issue on which Roman Catholic Church teachings are currently lagging behind scientific advances. The son of a socialist truck driver, Scola is one of the closest heirs to Benedict XVI, combining conservative views with progressive social advocacy on issues like immigration and poverty. He is Italian but is not associated with the Vatican bureaucracy, whose image has been badly tarnished by infighting in recent years.
ODILO SCHERER: The 63-year-old Brazilian is archbishop of Sao Paolo, home to five million faithful in a country that has the world's biggest Catholic population. Scherer, whose family descended from German immigrants, is seen as a moderate conservative with charisma and openness, as well as a good administrator. He has fought against declining traditional values and is concerned about the growing strength of evangelical churches across the developing world. Scherer is well acquainted with social problems in Sao Paulo, a cosmopolitan city of 11 million people facing high poverty rates, crime, youth unemployment and lack of basic services. On his archdiocesan website and in newspapers, Scherer regularly offers commentary on key issues. He is also very active on Twitter, boasting 20,000 followers of his account @DomOdiloScherer.
MARC OUELLET: Canada's former archbishop of Quebec, 68, Ouellet now heads the influential Congregation of Bishops and is seen as the leading North American candidate for the papacy. Known for his conservative theological views – very much in line with Benedict's – Ouellet could be favoured for the pull he may have in the increasingly secularised West. Supporters hope he would also crack down on the unruly Curia, the Vatican's government. He is the head of the Pontifical Commission for Latin America, where he has a strong following. The mainstream conservative churchman who once said becoming pope "would be a nightmare" is an insider with strong connections to the Curia. Branded the "Iron Cardinal" by Canadian media for his buttoned-down views, Ouellet could widen a rift between conservatives and reformists, according to Gilles Routhier, head of Laval University's theology faculty in Quebec City.
PETER ERDO: Archbishop of Budapest since 2002 and a canon law expert who has taught at the Pontifical Lateran University in Rome, the 60-year-old Hungarian is known for his efforts to combat secularisation.
CHRISTOPH SCHOENBORN: The archbishop of Vienna, 68, has called for a re-examination of the issue of priest celibacy in the wake of the child sex abuse scandal.
JOSE FRANCISCO ROBLES ORTEGA: The 64-year-old archbishop of Guadalajara, Mexico's second largest city, is described as reserved and lacking charisma. He has taken a stand against the rampant violence linked to drug traffickers in his country, as well as rising secularism.
LUIS ANTONIO TAGLE: The archbishop of Manila was last year appointed the Church's second youngest cardinal. The 55-year-old is tipped as an outsider to watch for his dynamism, charisma and stellar rise. His relative youth stands against him, but he is very popular in Asia and has worked closely with Benedict.
TIMOTHY DOLAN: Archbishop of New York and a "modernist conservative", 63-year-old Dolan is media savvy – a plus in today's social media society.
SEAN O'MALLEY: The staunchly pro-life archbishop of Boston, 68, is a member of the Capuchin order who became the first cardinal with a blog in 2006. He has vowed a zero-tolerance policy against sexual abuse by priests and settled dozens of claims.
WILFRID NAPIER: South African Cardinal Wilfrid Fox Napier is the 71-year-old archbishop of Durban who has said the Church is in a "profound crisis" and needs a new pope to implement "spiritual renewal". AFP