Vatican City • At a Mass in the Sistine Chapel on Friday attended by the cardinals who had elected him their leader the day before, Pope Leo XIV spelled out his missionary vision for the church. But first he told the cardinals that his leadership would continue to depend on them.

Pope Leo XIV has celebrated his first Mass, a day after his historic election as the first U.S.-born pope in the church’s 2,000-year history. The election of cardinal Robert Prevost as the new pontiff overcame the traditional prohibition against a pope from the United States.

Pope Leo XIV's formal inauguration Mass to mark his appointment will take place in St. Peter's Square on Sunday May 18, the Vatican said in a statement on Friday.