Cardinals Angelo Scola of Milan and Odilo Scherer of Sao Paulo are the two most often-mentioned frontrunners in the conclave to elect the next Roman Catholic pope that opens on Tuesday.
But about a dozen names of "papabile" (possible popes) are circulating among Vatican watchers in Rome. The 115 cardinals can turn to other candidates if the favourites fail to build momentum towards the necessary two-thirds majority, or 77 votes.
Identifying trends is difficult because there are no declared candidates and electors are sworn to secrecy about their preparations for the conclave and what happens inside the Sistine Chapel while they vote.
A strong candidate could win a large minority of votes in the first voting round on Tuesday afternoon. But if he fails to build on it in subsequent voting rounds - two each in morning and afternoon sessions - the cardinals could look elsewhere.
Here are the dozen most frequently mentioned names:
- Angelo Scola (Italy, 71)
Springboard to the papacy, and the leading Italian candidate. An expert on moral theology, Pope Benedict moved him there from Venice - another papal launching pad - in 2011 in what some saw as a sign of approval.
Scola was long close to the conservative Italian Catholic group Communion and Liberation, which Benedict also favoured, but has kept his distance in recent years.
He is familiar with Islam as head of a centre for Muslim-Christian understanding, with wide contacts abroad. His dense intellectual oratory could put off cardinals seeking a charismatic preacher.
- Odilo Scherer (Brazil, 63)
The leading candidate from Latin America, where 42 percent of the world's Catholics live. Archbishop of Sao Paulo, the biggest diocese in the country, he is a conservative there but would rank as a moderate elsewhere.
His German family roots and stint working in the Vatican Curia give him important links to Europe, the largest voting bloc. Italian media say he enjoys support among Curia cardinals opposed to Scola.
He is known for a sense of humour and tweets regularly. The rapid growth of Protestant churches in Brazil that woo away Catholics could count against him.
- Marc Ouellet (Canada, 68)
The Vatican's top staff director, as head of the Congregation for Bishops. An academic theologian of the Ratzinger school, he once said becoming pope "would be a nightmare".
Well-connected within the Curia, the Vatican bureaucracy, he also has ties to Latin America from teaching there and now heading a Vatican commission on the region.
Factors against him include his rough time as archbishop of Quebec, where his conservative views clashed with the very secular society there and he left apologising for any hurt he had caused. His bland speaking style is another drawback.
- Sean O'Malley
The "clean hands" candidate if cardinals make settling the sexual abuse crisis a top priority.
Appointed in 2003 to Boston, the third diocese in a row where he was called in to clean up after sexual abuse crises, he sold off Church properties to pay damages. He also shut down little-used churches despite strong protests, a sign of management mettle despite his humble appearance in the brown habit of his Capuchian Franciscan order.
Conclaves have long been wary of picking a "superpower pope" from the U.S. but his calm authority and Franciscan humility have eased many of these concerns.
- Timothy Dolan (USA, 63)
Archbishop of New York and head of the U.S. bishops, has made his Church a conclave player like never before.
His humour and dynamism impress many in the Vatican, where both are often missing, and attract cardinals who want a strong manager and a charismatic preacher. His fans say Dolan would bring stricter American management to the Curia and a renewed self-confidence in standing up for orthodox Church teachings like opposition to abortion and same-sex marriage.
His detractors find him too informal, "too American," and fear he might use too stiff a broom to clean out the Curia.
- Leonardo Sandri (Argentina, 69)
A "transatlantic" born to Italian parents in Buenos Aires who rose to hold the third-highest Vatican post as chief of staff in 2000-2007.
A "safe pair of hands", he is often seen as an ideal Secretary of State, or deputy to the pope, rather than pontiff. He has no pastoral experience and his Curia job overseeing Eastern Rite churches is not a power position in Rome.
He recently said women should be given more leadership positions in the Church. One drawback could be that he is identified with John Paul's papacy, when sexual abuse cases were swept under the carpet.
- Peter Erdo (Hungary, 60)
Ranks as a prime compromise option if the conclave's European majority fails to elect an Italian and fears letting the papacy go overseas.
Two terms as head of a European bishops council and strong links with African church leaders signal Erdo's wide contacts. A canon lawyer by training and conservative in his views, he has also been a pioneer in the New Evangelisation drive to revive the Catholic faith, a priority mentioned by many cardinals in pre-conclave debates.
On the minus side, he is not a dynamic preacher and has only an average record for management in his own archdiocese.
- Christoph Schoenborn (Austria, 68)
A former student of Pope Benedict who became Vienna archbishop after a sexual abuse scandal. A gifted polyglot preacher and editor of the Church's catechism, he was seen as "papabile" in the 2005 conclave but also too young at the time.
He has openly criticised the Vatican's slow handling of abuse cases and supported cautious reforms, including more respect for gays in the Church. That could dent his support among some cardinals, as could an active dissent movement by some Austrian priests that he has chosen to talk with rather than discipline strictly.
- Peter Turkson (Ghana, 64) is the top African candidate. Head of the Vatican justice and peace bureau, he is spokesman for the church's social conscience and backs world financial reform.
The prospect of an "Obama moment" with the first pope from sub-Saharan Africa fascinates many Catholics, but Turkson faces formidable obstacles. He is seen as campaigning too openly for the post, breaking a strong Vatican taboo, and critics say his financial reform plan was naive.
He upset many bishops by showing a sensational anti-Muslim video at a recent Vatican synod, raising doubts about his diplomacy and views on Islam.
- Joao Braz de Aviz (Brazil, 65), the former archbishop of Brasilia, brought fresh air to the Vatican department for religious congregations when he took over in 2011 and eased some strains created by his more dogmatic predecessor.
He backs the support for the poor in Latin America's liberation theology, but not its leftist political activism. When he was made a cardinallast year, he said it was time for a non-European pope and his passport could help if the conclave needs a compromise candidate.
He has kept a low profile in Rome and has not stood out as a dynamic preacher or energetic manager.
- Gianfranco Ravasi (Italy, 70) is Vatican culture minister and Bible expert who represents the Church to the worlds of art, science, culture and even to atheists.
A brilliant preacher and writer, quoting everyone from Aristotle to Amy Winehouse, he is seen as a possible Italian alternative to Scola. Pope Benedict asked him to preach at Curia Lenten exercises this year, a sign of his approval.
But the now retired pope has also discreetly criticised Ravasi's meetings with atheists as ineffective and his profile seems out of step with the preacher-manager that cardinals say they want to replace the theologian Benedict.