Papal conclave explained from 'virtual Sistine Chapel'
11 March 2013 Last updated at 06:48 GMT
Cardinals have set Tuesday as the start date for the conclave to select a new pope.
The first vote is scheduled for the afternoon, following a morning mass.
So how exactly does the Roman Catholic Church select its next leader?
No cameras or journalists are allowed in the conclave, but Philippa Thomas explains what to expect, from the BBC's own "virtual Sistine Chapel".