Cardinals will meet next month in a secret conclave to elect the next pope, the Vatican has said.
The closed-door meeting will start inside the Sistine Chapel on 7 May and will involve some 135 cardinals from across the world.
It follows the death of Pope Francis who died on Easter Monday and whose funeral was held on Saturday.
There is no timescale as to how long it will take to elect the next pope, but the previous two Conclaves, held in 2005 and 2013, lasted just two days.
Vatican spokesman Matteo Bruni said cardinals will take part in a solemn mass at St Peter’s Basilica, after which those eligible to vote will gather in the Sistine Chapel for the secretive ballot.
Once they enter the Sistine Chapel, cardinals must have no communication with the outside world until a new Pope is elected.
There is only one round of voting on the first afternoon of the conclave, but the cardinals will vote up to four times every day afterwards.
A new pope requires a two-thirds majority – and that can take time.
Each cardinal casts his vote on a simple card that says, in Latin: “I elect as Supreme Pontiff” to which they add the name of their chosen candidate.
If the conclave completes its third day without reaching a decision, the cardinals may pause for a day of prayer.
Outside the Sistine Chapel the world will be watching for the smoke from the chimney.
If the smoke is black, there will be another round of voting. White smoke signals that a new pope has been chosen.