VATICAN CITY, May 5, 2025 (BSS/AFP) - Catholic cardinals will enter a sealed conclave this week to choose a new pope, with the Church's 1.4 billion members holding their breath over an uncertain outcome.

Around 133 "Princes of the Church" will meet Wednesday to elect from among their number a successor to Pope Francis, who died on April 21 aged 88.

At issue is whether the new pontiff will follow the popular Argentine's progressive line, or will the Holy See pivot to a more conservative traditionalist?

Francis ran the Church for 12 years and appointed 80 percent of the cardinal electors.

Hailing from five continents and with around 70 countries represented, the group is the largest and the most international ever.

Some experts say the progressive camp will have the edge, seeking a pope that will follow in Francis's footsteps and energise his supporters.

- 'Calm the waters' -

But no one can predict how voting will go once the cardinals are shut inside the Sistine Chapel and begin an open-ended series of votes seeking a two-thirds majority for one of their number.

Among the pilgrims and sightseers who gathered outside St Peter's Basilica at the Vatican on Sunday, as the Church ended Francis's nine-day mourning period, opinions varied widely.

Canadian priest Justin Pulikunnel did not hide his frustration at the direction Francis tried to take the Church, seeking a return to more traditional leadership.

"Well, I hope and I pray that the new pope will kind of be a source of unity in the Church and kind of calm the waters down after almost a dozen years of destabilisation and ambiguity," he said.

But others like Valeria Sereni, a 30-year-old Italian, expressed hope that the new pope would follow in Francis's more open spirit on issues of sexuality, human rights and the environment.

"Francis has opened a new path and someone has to carry it on," she said.

"We'll be very fortunate if we find somebody as good as the previous one," agreed 72-year-old Wayne Gosper from Australia, sounding a note of caution that secular politics might influence the cardinals' choice.

"The world is turning right wing, right? And we lost a left-wing pope," he said.

The conclave begins Wednesday afternoon and could continue for days, weeks or even months before the smoke from the chapel's chimney turns white to signify a new pontiff has been chosen.

But on Monday, lengthy preparatory meetings known as general congregations were continuing both with morning and afternoon sessions for the first time.

All cardinals are invited to these, not just those under 80 who are eligible to vote in conclave, and they take the opportunity to discuss the issues that will face Francis's successor.

These are not supposed to be political events, but the prelates are getting to know each other and some admit that they discuss names at meals and on the sidelines.

"Nobody campaigns, for crying out loud. That would be extraordinarily stupid and indiscreet, and improper and counterproductive," said Cardinal Timothy Dolan, archbishop of New York.

"But you just want to get to know folks, and it works well," he said on his own podcast.

- 'Spectacular' conclave? -

"And I don't apologise for the fact. That should be. I mean, we would speak about one another. We would speak about the guys that we find tantalising," Dolan said.

"But that's different from politicking, because we always say grace builds on nature, right? So, we know, ultimately, it's the illumination of the Holy Spirit, for which we pray to be open."

Dolan himself is among the conservatives whom cardinals might vote for, while Luis Antonio Tagle from the Philippines is a leading candidate among progressives within the Church.

From Europe, Italian cardinals Pierbattista Pizzaballa, the Latin Patriarch of Jerusalem, and Pietro Parolin, secretary of state under Francis, are some of the best known "papabili", or potential popes.

But many more names have been discussed, and just like when Francis -- then an Argentinian known as Jorge Bergoglio -- was picked in 2013, a surprise candidate could emerge.

Vatican affairs specialist Marco Politi told AFP that the conclave could be "the most spectacular in 50 years".