A papal conclave is set to begin in Vatican City starting May 7, during which cardinals from around the world will elect the next leader of the Roman Catholic church. The tradition occurs any time a pope dies or resigns from the office. Pope Francis died April 21, the day after Easter.

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. The conclave will start behind the closed,