Final preparations are underway for the conclave, the secretive process where the College of Cardinals sequester at the Vatican to vote on who will be the next Pope.

The centuries-old tradition begins Wednesday. Beginning at 9:30 a.m. Chicago time, 133 cardinals will gather inside the Sistine Chapel and lock the doors to host their first and only vote of the day. Voting sessions on subsequent days, should they be needed, will occur regularly in the morning and afternoon until a pope is selected, by a two-thirds majority.

“It is clear there is a bit of tension in the air,” NBC 5’s Mary Ann Ahern reported from Vatican City Wednesday. “The first vote takes place at 12 p.m. Chicago time, but no one anticipates a two-thirds majority on the very first vote.”

After each vote, ballots are burned in a special stove. Black smoke signals no decision, while white smoke means a new pope has been chosen. 

If no candidate is chosen after three days, cardinals will take a spiritual pause to pray, and have informal discussion.

4 of 7 American Cardinals taking part in Conclave voting have ties to Chicago

Ahern added that there are no official candidates for the papacy!

“While several names are mentioned more often than others, it does appear the process is wide open,” Ahern said.

When will a new Pope be chosen?

Back in the 13th century, it took almost three years — 1,006 days to be exact — to choose Pope Clement IV’s successor, making it the longest conclave in the Catholic Church’s history.

This time around, it’s reasonable to assume the conclave will be much, much shorter.

While cardinals this week said they expected a short conclave, it will likely take at least a few rounds of voting. For most of the past century, it has taken between three and eight ballots to find a pope. John Paul I — the pope who reigned for 33 days — was elected on the third ballot in 1978. His successor, John Paul II, needed eight. Francis was elected on the fifth in 2013.