Who, what, why and when: An expert's view on the conclave

The announcement of the date for a conclave kicks off a process that could see a successor to Pope Francis elected by the end of next week.

John L. Allen Jr, editor of online Catholic newspaper Crux and author of numerous books on the Vatican, offered AFP some insights on Monday into how it will play out.

Who appears the favourite so far?

"Certainly the early favourite has to be Cardinal Pietro Parolin. He was the secretary of state for 12 years of the Francis papacy, so he has the greatest visibility and is probably best known to most of the other cardinals.

"He represents a vote to continue the substance of the Francis papacy but without the maverick instinct of Pope Francis.

"He would be seen as a more sort of conventional and predictable figure and I think there are a lot of cardinals for whom predictability and an absence of bombshell surprises is something they would see as desirable."

135 cardinals are eligible to vote: is this a record number?

"In recent experience, it's the largest number of cardinals who are taking part in a conclave.

"Recent popes have gone way over the 120 limit quite often in terms of the cardinals they named, with the thought that by the time this (the conclave) actually happens, a number of them will have aged out or died.

"It just so happens that Pope Francis just named a new cohort of cardinals. So the tank is full."

Asked about those too sick to travel to Rome, he added: "If you're not physically present in the conclave, then you don't vote. There is no mail-in ballot for the election of a pope. "

How long will the conclave last?

"These cardinals don't know one another very well," Allen said.

"This could be a prescription for a protracted conclave because it would be difficult to form consensus among people who don't have a strong sense of where one another is coming from.

"But the flip side of that, is it could also be a prescription for a very short conclave.

"A large number of cardinals who feel sort of lost and adrift may simply play follow the leader, looking to sort of well-known, well-established figures who have been around a long time and putting themselves in their hands."

He added: "There is an extraordinarily powerful incentive built into the system not to let this go too long.

"Because the last thing the cardinals want is to give the world the impression that they are divided and that the church is adrift and in crisis."

What will the cardinals be looking for?

"Every conclave to some extent shapes up as a referendum on the papacy that's just ended -- do we want to keep it going and therefore find somebody who stands in continuity with the previous pope, or do we want to make a change?

"In 2005, the vote was overwhelmingly for continuity. That's how you got to Pope Benedict XVI, who had been John Paul's right-hand man, in four ballots.

"And in 2013, the vote was overwhelmingly for change. That's how you got to Jorge Mario Bergoglio of Argentina in five ballots.

"This time, I think it is far less clear which of those two options is going to prevail. I think instead, you're likely to get a mix of continuity and change."

What qualities will a new pope need?

"One, you want somebody who could be an effective evangelist, a missionary.

"There's a great sense that there are certain parts of the world -- particularly Europe, but more broadly the West -- where the faith is in trouble, where mass attendance is going down, vocations to the priesthood and religious life are going down, the public influence of religion in some ways is going down.

"You want somebody who could inspire a renaissance in the faith."

Secondly, "we live in a time of great geopolitical uncertainty and change.

"You see the rise of authoritarian governments in various parts of the world, (and) tremendous economic volatility... Old alliances seem to be falling apart."

He added: "There will be a desire for somebody who has the capacity to navigate the ship of state through the storms.

"So somebody with some sort of diplomatic and geopolitical experience."

Thirdly, the Vatican has administrative problems. "It is living through a severe financial crisis. Its pension fund is on the brink of insolvency.

"There is a sense that while Pope Francis launched some ambitious Vatican reforms, those remain unfinished business.

"And so you're also going to want somebody who would be a strong governor, who is a strong administrator, manager."