What is a conclave? Inside room where new Pope and leader of Catholic church chosen

With the death of , many have been left wondering how a new pope is selected, in the wake of the .

The highly secretive meeting - the Conclave - to choose the next pope takes place inside the Sistine Chapel, complete with its one-of-a-kind ceiling painted by Michelangelo and lasts for however long it takes those inside to decide on the next .

Around two to three weeks after the pope's funeral, the College of Cardinals will get together in the chapel for the conclave. Technically, any baptised male Catholic is eligible to become pope, although for the last 700 years, they have always been chosen from within the College of Cardinals.

Throughout history most popes have been Europeans; the current Pope is the first non-European in 1,300 years, having been born in 1936 in as Jorge Mario Bergoglio. On the day of voting, the Sistine Chapel is physically sealed off and the cardinals, who have taken an oath of secrecy, are locked inside.

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The term conclave itself is Latin for "locked room" and only cardinals aged under 80 get a chance to vote. The currently has 252 cardinals, of which 138 fit the age requirement. It's not clear how the 120 are chosen, again another secret only known by those inside the conclave.

The conclave's first day begins with the special mass, after which the cardinals file into the Sistine Chapel chanting prayers and hymns, imploring saints and the Holy Spirit to help them pick a pope. Each cardinal places his hand on a book of the Gospels and pledges "with the greatest fidelity" never to reveal the details of the conclave.

The master of the papal liturgical celebrations, a Vatican official then cries "Extra omnes" Latin for "All out" and everyone except the cardinals leaves and the voting can begin. Cardinals can be excommunicated if they leak information about what takes place and the chapel is swept for listening devices before and after the conclave.

Each cardinal writes his choice on a paper with the Latin words for "I elect [xx] as supreme pontiff." They approach the altar one by one and say: "I call as my witness, Christ the Lord who will be my judge, that my vote is given to the one who, before God, I think should be elected."

The folded ballot is placed on a round plate and slid into an oval silver-gold urn. Once cast, the ballots are opened one by one by three scrutineers, who note the names down and read them aloud. Cardinals can keep their own tally on a sheet of paper provided but must turn their notes in to be burned at the end of voting.

The winning candidate must get two-thirds of the votes to secure his place as the next Pope. Once the ballots are counted, they are burned in a stove inside the Sistine Chapel. A second stove burns a chemical sending up a smoke signal through a chimney to the outside world: Black smoke means a new pope has not been selected, white smoke means one has.

If no one is elected after three days, voting pauses for up to one day. Voting resumes and if no pope is elected after another seven ballots, there is another pause. This keeps repeating until about 12 days of balloting have passed. If no one is selected after 33 rounds, the cardinals go to a runoff of the top two contenders, under a relatively new rule introduced by Pope Benedict. Unlike in previous rounds, those two candidates cannot cast ballots in this final vote.