Roman Catholic cardinals have been locked into the Sistine Chapel, beginning their secret election conclave to vote for the new pope.
The cardinals are cut off from all contact with the outside world
Before the door was closed, the 115 eligible cardinals swore an oath of secrecy and fidelity to the Church.
The cardinals will be shut off from the outside until a new pontiff is chosen.
They will now decide whether to take a first vote on Monday or wait until Tuesday, with all eyes on the chimney that will signal results with smoke.
Thousands of people are already in St Peter's Square, many watching for any sign of smoke from the chapel chimney.
Bells to toll
Up to four ballots a day will be held until a successor to Pope John Paul II is chosen.
Pope John Paul II died on 2 April and was buried a week later.
Ballot papers are burned after every second vote in a stove inside the Sistine Chapel.
Chemicals are added to colour the smoke - black smoke signals failure to agree on a candidate, while white smoke means a new pope has been chosen.
This time, the white smoke will be accompanied by the ringing of the bells of St Peter's Basilica.
Clad in their crimson robes and caps, and chanting the Litany of Saints, the cardinals walked slowly into the Sistine Chapel from the Hall of Blessings in the Apostolic Palace.
The cardinals were led by altar servers carrying candles, the Book of Gospels and a crucifix.
As they entered the chapel, covered in Renaissance frescoes including Michelangelo's dramatic Last Judgement, they took their places at two rows of tables along the walls.
Cardinal Joseph Ratzinger, Dean of the College of Cardinals, read out the oath of secrecy in Latin.
115 cardinals take part
Two other eligible cardinals are too ill to attend
Must be aged under 80
Come from 52 countries
58 from Europe
Italy (20) and US (11)
0730: Cardinals celebrate Mass in hotel
0900: Morning voting starts
1600: Afternoon voting starts
1200 & 1900: Smoke comes out
All times local (GMT+2)
In it the cardinals swore "to observe with the greatest fidelity and with all persons, clerical or lay, secrecy regarding everything that in any way relates to the election of the Roman Pontiff".
Then one by one, in order of precedence, the cardinals filed to the centre of the chapel and placed their hands upon the Gospels to take an individual oath, again in Latin:
"And I, [name], do so promise, pledge and swear. So help me God and these Holy Gospels which I touch with my hand."
Afterwards the master of Vatican liturgical ceremonies, Archbishop Piero Marini, called out the words "Extra Omnes" ["Others Out"] - the order for all those not taking part in the secret conclave to leave. The doors were then closed and the live television pictures ended.
Strict security measures have been imposed to ensure the secrecy of the conclave is kept.
Parts of the Vatican have been sealed off, and all staff who will come into contact with the cardinals have taken a vow not to divulge anything of what they see or hear.
Mobile phones, newspapers and television are banned, and the Sistine Chapel has been swept to check for bugging devices.
The cardinals will shuttle between the Domus Sanctae Marthae hotel - nestled within the city-state's walls, where they are staying - and the Sistine Chapel until the conclave is finished.
Pope John Paul II was elected after eight ballots. This time, the cardinals may come to a decision within days, but previous conclaves have been known to go on for months.
The new pope is elected with a two-thirds majority, unless, after 34 ballots, cardinals decide to change the rules in favour of a simple majority.
Full details of the actual vote will not be published for 100 years.