Pope Benedict XVI began a week-long spiritual retreat out of the public eye on Monday ahead of his resignation on February 28, with the field of candidates to succeed him still wide open.
Benedict and some of his top cardinals will devote this week to daily prayers in a frescoed private chapel in the Apostolic Palace in the Vatican during Lent -- a period of penitence in the Christian calendar before Easter.
The cardinal leading the prayers said he hoped the retreat would serve as a period of respite for the pope following his momentous decision to step down.
"After the storm, my task will be to create a moment of oasis," Gianfranco Ravasi, who is effectively the Vatican's culture minister and is seen as a long-shot contender for the papacy, told Vatican radio.
The retreat is a yearly tradition -- one of several regular appointments that the pope has stuck to in the wake of his historic announcement last week.
Following the retreat, the pope will receive Italian President Giorgio Napolitano on February 23, celebrate his final Sunday prayer on February 24, and hold a last audience before tens of thousands of faithful on February 27.
Benedict will formally step down as pope on February 28 at 1900 GMT, shortly after being whisked away from the Vatican by helicopter for the last time.
His role and title following his resignation have still not been determined and no date has been set for the conclave of cardinals to elect him.
The resignation will set up an unprecedented situation in modern Catholic history where popes usually serve until death -- a pontiff and his predecessor both living in the Vatican just a stone's throw away from each other.
The idea that a pope -- whose election is believed to be divinely inspired -- can resign has been a shock to many Catholics around the world.
Vatican observers say Benedict's move could set a precedent for future popes, whose advancing age often hampers their effort to govern the Church.
The conclave to elect a new pope usually begins between 15 and 20 days from the death of a pope according to the Apostolic Constitution, which would put the date for the start of the deliberations on or around March 15.
But canon lawyers are hard at work to see if the date could be brought forward to earlier in March to avoid any possible overlap with the Holy Week before Easter, which begins on March 24 ahead of Easter Sunday on March 31.
No clear favourite for the papacy has emerged, unlike for the run-up to the last conclave in 2005 when Cardinal Joseph Ratzinger was already seen as the candidate who could best bring together different factions in the Church.
"There is no obvious favourite," said John Allen, a Rome-based Vatican specialist who writes for the National Catholic Reporter, a US publication.
One popular contender, Canadian cardinal Marc Ouellet, is "basically a photocopy of Ratzinger," Allen said. Ouellet is "a man who lives in his mind, not a man for government" and seems "a little grey" in public, he added.
This week's spiritual retreat in the Vatican will include 17 "meditations" written and read out by Ravasi, some of which are being made available by Vatican radio as podcasts so Catholic believers can pray along with the pope.
In his first prayer late on Sunday, Ravasi compared the pope to the Biblical figure of Moses who prayed on a mountain while battles raged in the valley.
"This image represents the main function, your function, for the Church, that is of intercession," he said.
"We remain in the valley... where there is dust, fear, terror, nightmares but also hope, where you have been for these past eight years with us.
"From now on, however, we will know that on the mountain there is your intercession for us."