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The interior of the Sistine Chapel

How does the Vatican choose a new pope? 

Image: JurateBuiviene /

New popes don’t come along very often, and the election of the pontiff is unlike any other democratic process on Earth.

Who elects the pope?

A new pope is elected by cardinals, the senior members of the Catholic clergy who are well-known for their distinctive red garb. Cardinals eligible to vote for the new pope – i.e., those under the age of 80 – travel to the Vatican from all corners of the globe. They then form what’s known as a conclave, which is the body responsible for choosing the next pontiff.

For around the first thousand years of the papacy, things weren’t quite as clear-cut as this, with various factors coming into play. Lower clergy and members of the wider Roman community could have their say, while secular leaders such as the Holy Roman Emperors would inevitably meddle in proceedings.

The lack of a formalised process meant there could be all kinds of peculiar twists and turns. An 11th-century pope, Gregory VI, literally purchased the papacy from his predecessor. A 2nd-century pope, Fabian, was chosen by the Roman clergy on the spur of the moment because a dove happened to fly down and perch on his head during a church gathering.

It was in 1059 that Pope Nicholas II decided to tighten things up by decreeing that popes would be chosen by cardinals only. This curbed the influence of external figures like emperors and aristocrats, paving the way for the independent conclave process we know today.

How does the conclave take place?

Having assembled in the Vatican, the cardinals file into the Sistine Chapel, where the time-honoured conclave process takes place beneath the iconic ceiling fresco of Michelangelo. The grandeur of the religious art ensures that – in the words of Pope John Paul II – ‘everything is conducive to an awareness of the presence of God.’

Once the cardinals have taken their seats inside the Sistine Chapel, all those not involved in the conclave process are ordered to leave with the command ‘Extra omnes!’ (‘All out’). With the doors then closed, the cardinals commence the voting process. An initial ballot may be held that first day, with up to four ballots per day – two in the morning, two in the afternoon – taking place after that. This continues until one cardinal gains a two-thirds majority, the threshold for becoming pope.

The cardinals write the names of their choices on ballot papers, then take turns approaching the altar. Here, facing Michelangelo’s colossal fresco of The Last Judgement, they submit their ballots with the words: ‘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.’

What happens after voting?

Randomly selected cardinals gather the ballots and read out the names of all those who’ve received votes. The collected ballots from the entire morning or afternoon session are then placed inside a specially-installed stove and set alight. Certain chemicals are added to the mix to produce either black or white smoke. Black smoke signifies to the crowds outside that the voting session hasn’t been successful, while white smoke signifies that a new pope has been elected.

The tradition of the smoke has fuelled a long-standing conspiracy theory known as the Siri thesis. This stems back to the conclave of 1958 when it was reported that white smoke strangely gave way to black smoke.

According to Siri thesis believers, the white/black smoke fluctuation was due to a certain Cardinal Giuseppe Siri being elected pope, and then immediately being forced to give up the papacy for nefarious political reasons. According to believers, Angelo Giuseppe Roncalli – the cardinal who emerged from the conclave as Pope John XXIII, was a false pontiff.

No evidence backs up the theory, and Siri himself never claimed there had been such shenanigans in the Sistine Chapel.

What happens when a cardinal achieves a two-thirds majority?

Once a cardinal attains the majority vote, he formally accepts his new status and announces the new name he will use as pope. Adopting a papal name is a tradition that goes back to 6th-century pontiff John II, who believed his birth name Mercurius was inappropriate because of its link to the pagan god Mercury.

The new pope then goes to a special part of the Sistine Chapel known as the Room of Tears, so-named because of the intense emotions that the now former-cardinal is sure to be feeling. This is where he’ll change into his papal clothes, and it’s also his final opportunity to brace himself before facing the Vatican crowds, and the whole world, as the new pope.

How secret is the whole process?

Very. The whole process is sealed off from the outside world, with the cardinals swearing an oath of secrecy. The Sistine Chapel is swept for hidden microphones, and signal jammers prevent electronic communications in or out of the Vatican.

The need to isolate the electors from the outside world meant that conclaves used to be a pretty uncomfortable experience. The often elderly cardinals would basically have to crash in makeshift lodgings, sharing limited toilet facilities and sleeping on cots that, in the words of English Cardinal Basil Hume, were presumably provided ‘by a seminary for very short people’. During the conclave of 1978, hot weather even led some fed-up cardinals to rip away the seals placed to keep windows shut for the duration of the conclave.

Fortunately for the cardinals, those days are no more. Beginning with the conclave of 2005, they’re all put up in a spacious, air-conditioned building called the Domus Sanctae Marthae. It’s so comfortable that it has also served as the primary residence of Pope Francis himself.