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.

Ukrainian President Volodymyr Zelenskyy will be attending Sunday's inauguration of Pope Leo XIV, a top aide has said. The recently elected pope will formally take on his role as head of the Catholic Church with a Mass in St.

The ceremony will mark the official start of Leo’s papacy, as he will formally receive the pallium, a woolen stole symbolising his role as shepherd, and the fisherman’s ring.