ROME — The new Chicago-raised Pope Leo XIV faces an immediate challenge in his native country: taming the brawling U.S. tribe of Catholics, riven by political divisions that have thwarted the will of his predecessors.

Pope Leo XIV celebrated his first Mass in the Sistine Chapel where he was elected less than 24 hours earlier, warning of the dangers caused by a lack of faith and hoping the Catholic Church could be a beacon lighting the world's "dark nights".

The man who is now known as Leo XIV becomes the 267th Bishop of Rome and the successor to Francis, one of the most liberal and controversial Catholic leaders ever. Leo’s own politics are thought to be more moderate.