Catholic cardinals gathered at the Vatican this week to elect the successor to Pope Francis, who died on April 21.

Leo XIV celebrated his first Mass as pontiff at the Vatican's Sistine Chapel on May 9, the day after stunning the world as the first pope from the United States in the Church's history. Leo, formerly Cardinal Robert Francis Prevost,

Robert Prevost, who took the name Pope Leo XIV, led his first Mass at the Sistine Chapel. He is the first American pope in Catholic church history.