There are currently 135 cardinals who are under age 80 and eligible to vote in the conclave, hailing from 71 different countries in the most geographically diverse conclave in history. Already two have formally told the Holy See that they cannot attend for health reasons, bringing the number of men who will enter the Sistine Chapel down to 133.

The conclave, which will kick off on Wednesday, will be held behind the closed doors of the Sistine Chapel. It generally lasts several days and, in some cases, weeks. The term conclave comes from the Latin term “con clavis”, meaning “with a key”, a reference to the tradition of locking the cardinals away until a new pope is elected.

All of the 133 cardinals expected to take part in the secret conclave to elect a new pope have arrived in Rome, the Vatican said on Monday, with the race to succeed Pope Francis seen as wide open.