Within weeks, Catholic cardinals from around the globe will descend on the Vatican to elect a new pope. For the first time in six centuries, they will not be mourning their previous leader’s death.

Pope Benedict XVI has stunned the world with his resignation, citing his poor health. He will be replaced by the cardinal who garners the majority of votes in a centuries-old ritual.

Cardinals summoned to the Vatican

The meeting of cardinals to elect a new pope by secret ballot behind closed doors is known as the conclave (derived from Latin, it literally means “with key”).

A rule introduced by Pope John Paul in 1996 states that a conclave cannot start for at least 15 days after the pope dies (or, in this case, resigns). But according to reports, Pope Benedict may change that to allow the conclave to begin in time to elect a new pope before Easter. 

The College of Cardinals has the exclusive right to elect a pope, but members who are 80 or older cannot vote. A maximum of 125 cardinals can cast ballots.

All cardinals must be present for the vote, unless they are seriously ill or have some other “grave impediment.”

Cardinals who are sick but can still travel are allowed to have a nurse by their side. Two doctors will also be on standby during the conclave in case of emergencies.

The cardinals must remain under “lock and key” in the Vatican for as long as it takes to elect a new pope.

Choosing a pope

The election can take days or weeks. In the past, the process has dragged on for months and some cardinals even died before a pope was chosen.

Theoretically, any baptized Catholic male can become the pope, but it’s understood that the honour will be bestowed upon a cardinal.

The voting takes place in the Sistine Chapel under strict rules, which include no contact with the outside world. Cardinals are not allowed to talk on the phone, go online or send out letters, except in cases of “proven and urgent necessity.”

They also cannot read newspapers or magazines and will have no access to TVs and radios.

The cardinals sleep, eat and pray in their designated lodgings during the conclave. There will be select priests on hand to hear their confessions. Housekeeping and cooking staff will also be available, but anyone who comes into contact with the cardinals must swear an oath of secrecy.

The voting process

Before voting starts, the Sistine Chapel will be checked from top to bottom to ensure that there are no hidden recording devices or cameras.

On the day when the conclave officially begins, the cardinals swear an oath of secrecy and take part in morning prayers and rituals.

Anyone who breaks the oath or other conclave rules will “be subject to grave penalties according to the judgement of the future Pope,” according to Vatican rules.

A single ballot can be cast on the afternoon of the first day of voting. There are specific instructions on how the ballot must look -- rectangular, with the words “I elect as Supreme Pontiff” (written in Latin) printed on the upper half.

The cardinals are to write the name of their preferred candidate on the bottom half of the ballot, taking care that their handwriting is not recognizable, and fold the paper in half.

The cardinals will keep casting ballots until the pope is elected by a two-thirds majority.

Scrutineers will check all the ballots as they are opened and counted. If the pope is not chosen, another round of voting will be announced. The ballots will then be burned, sending black smoke from the Sistine Chapel’s chimney to let the crowd waiting outside know that a leader has not yet been chosen.

Once two-thirds of the ballots have the same name, chemicals will be added to the burning papers to produce white smoke, indicating that the pope has been chosen. The bells of St. Peter’s Basilica will ring in celebration.

Once he is ready, the new pope will emerge on the balcony to greet the world.