The world’s gaze turns to the Vatican today as 133 cardinals from across the globe enter the hallowed Sistine Chapel to begin one of the most sacred and secretive rites in Catholicism—the conclave to elect the 267th Pope.

Under the grandeur of Michelangelo’s famed ceiling, the cardinals commenced a solemn process that will determine the spiritual leader of the Catholic Church’s 1.4 billion faithful. The day began with a Mass at St. Peter’s Basilica, presided over by 91-year-old Cardinal Giovanni Battista Re, Dean of the College of Cardinals, who also led the funeral rites for Pope Francis.

Here is a look at what happens inside the Sistine Chapel during a papal election.

First things first… each ballot that the 133 cardinal electors will use to choose the next pope is inscribed “Eligo in Summum Pontificem” (“I elect as Supreme Pontiff”.). The rectangular ballot bears the aforementioned Latin phrase at the top half, while the bottom half of the ballot is left blank for the cardinal to write the name of his chosen candidate.

According to the Apostolic Constitution Universi Dominici Gregis, the ballot is designed to be folded in half.

According to Vatican author Tiziana Campisi, each cardinal elector receives at least two or three ballots, distributed by the ceremonial officers.

The senior cardinal deacon then draws lots to appoint three scrutineers (those who count the votes), three infirmarii (those who collect votes from ill cardinals), and three revisers (those who verify the count).

“If any of those selected are unable to fulfil their roles due to illness or other reasons, new names are drawn in their place. This stage is known as the pre-scrutiny,” Campisi says.

Before the process of actual voting, all non-electors – including the secretary of the College of Cardinals, the Master of Papal Liturgical Celebrations, and the ceremonial officers – must leave the Sistine Chapel. The senior cardinal deacon then closes the doors, opening and closing them only as needed, such as when the infirmarii go to collect the votes of ill cardinals and return.

The voting process

Each cardinal, in order of hierarchy, writes the name of their chosen candidate on the ballot, then while making the ballot visible to everyone, carries it to the altar. There, a chalice is placed with a plate covering it.

Each elector says aloud, in Italian: “Chiamo a testimone Cristo Signore, il quale mi giudicherà, che il mio voto è dato a colui che, secondo Dio, ritengo debba essere eletto”. (“I call as my witness Christ the Lord, who will be my judge, that my vote is given to the one whom I believe should be elected according to God”.)

After saying these words, the cardinal then places the ballot on the plate and uses it to drop the vote into the chalice, bows to the altar, and returns to his seat.

Cardinals who are present but unable to walk to the altar due to illness give their folded ballot to one of the scrutineers, who take the ballot to the altar and deposits in the same manner, but now without reciting the oath.

If any cardinal is too ill to be in the chapel, the three infirmarii appointed at the start of the process visit them with a tray of ballots and a sealed box with a spacing where a folded ballot can be inserted. The infirmarii then brings the box back to the chapel, where it is opened in front of the electors.

Counting votes

“After all votes have been cast, the first scrutineer shakes the chalice to mix the ballots. The last scrutineer then counts them one by one, transferring them into a second, empty container. If the number of ballots doesn’t match the number of voters, all ballots are burned and a new vote is held immediately. If the count is correct, the ballots are opened and read,” an articles published on the Vatican website on Tuesday, May 6 reads in part.

The process of counting the votes entails the three scrutineers sit at a table before the altar. The first one reads out the name written on the ballot, passes it to the second one who confirms the name read out is the name written on the ballot, before giving it to the third scrutineer who reads it aloud for everyone to hear and records the vote.

In the event two ballots appear to be written by the same person and bear the same name, they count as one vote. If they show different names, both are invalid. In the event that the vote of a particular cardinal is declared invalid, this will not affect the overall vote, as it will remain valid.

Once all ballots have been read and the votes tallied, the final scrutineer pierces each ballot with a needle through the word Eligo and threads them together with string. The ends of the string are tied in a knot, and the ballots are stored for safekeeping.

Two-thirds majority

A two-thirds majority is required for a pope to be elected. Since there are 133 cardinal electors this time round, the next pope is the candidate that will garner at least 89 votes.

After verification is done that the electoral process was done according to the dictates of the laid down procedures, all the ballots are burned in a cast-iron stove first used in the 1939 conclave, before the cardinal electors leave the Sistine Chapel.

According to the Vatican, a second stove installed in 2005 is connected to a chimney visible from St Peter’s Square. “This is where the chemicals are added to colour the smoke: black if no Pope has been elected, white if one has.”

Voting rounds, spiritual pauses

Voting occurs four times daily – twice in the morning, twice in the afternoon. If, after three days, no candidate has been chosen, voting is paused for one day of prayer, informal discussions, and a brief spiritual exhortation by the senior cardinal deacon.

Voting then resumes. After every seven additional rounds without success, another pause and exhortation follow – first by the senior cardinal priest, and later, if necessary, by the senior cardinal bishop.

If still no Pope is elected after 21 votes, a final pause for prayer, dialogue, and reflection is observed. At this point, voting continues — but the cardinals may only choose between the two candidates who received the most votes in the previous round. Even then, a two-thirds majority is still required, and the two candidates in question are not allowed to vote.

The “Room of Tears”

According to Vatican tradition, once a Pope is elected, he is led to the “Room of Tears”. This is a small room next to the Sistine Chapel where he dons the white papal vestments for the first time.