Leo XIV, the first ever American pope, will be formally inaugurated as the 267th pontiff Sunday during a special Mass in St. Peter’s Square attended by world leaders, royalty, and thousands of believers.

Pope Leo XIV has taken the reins as leader of the Catholic Church, and on Friday, May 9, started his first full day as Pontiff with a mass at the Sistine Chapel, during which he called his election both a cross and a blessing.