Catholic cardinals convened in the Vatican's Sistine Chapel, where they will begin voting to elect a new pope. The 115 cardinal-electors were locked in the chapel after swearing an oath of secrecy. From now on the cardinals will eat, vote and sleep in closed-off areas until a new pope is chosen. They will hold a first vote, after which their ballot papers will be burned. The smoke that will drift out of the chapel's chimney early in the evening is likely to be black - meaning no pope has been elected. Beginning on Wednesday, two votes will be held each morning and afternoon - with ballots burned after each session - until one candidate obtains a two-thirds majority (77 votes). Then the smoke will be white, meaning the 266th bishop of Rome has been chosen.