Leo XIV held his first Mass as pope in the Sistine Chapel on Friday, in what was a private service for the 132 voting cardinals who elected him as the 267th leader of the world’s 1.4 billion Catholics a day earlier.

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.

Pope Leo XIV, the first American leader of the Catholic Church, previously known as Robert Francis Prevost, returned to the Sistine Chapel the day after his election to deliver a mass for the College of Cardinals, where he described his role as both a cross to bear and a blessing and urged church leaders to make themselves “small.”