Francis’ successor will be selected by cardinals at the conclave that began on May 7. Cardinals, known as the “princes of the church,” rank just below the pope in the Roman Catholic Church; together, they are known as the College of Cardinals. When a pope dies, the college chooses a successor.

Catholic cardinals are gathering at the Vatican to elect the successor to Pope Francis, who died on April 21. Voting will take place in the Sistine Chapel, with ballots continuing in succession until any candidate secures two-thirds of the available votes.

More than 130 Catholic cardinals on Wednesday began the secretive, centuries-old ritual to elect a successor to Pope Francis, opening the most geographically diverse conclave in the faith’s 2,000-year history.