A new book has revealed an unexpected breach during the secret conclave that elected Pope Leo XIV in May 2025: a cardinal reportedly carried a mobile phone into the Sistine Chapel despite strict security rules.
The claim appears in The Election of Pope Leo XIV, written by veteran Vatican journalist Gerard O’Connell and Argentine reporter Elisabetta Piqué. According to the authors, the device was discovered just as voting was about to begin beneath Michelangelo’s fresco The Last Judgment inside the Sistine Chapel.
The conclave is one of the Catholic Church’s most guarded traditions. Cardinals are cut off from the outside world, surrender electronic devices and remain isolated until a new pope is chosen. Signal-jamming technology is used to prevent outside communication.
Yet, the book says an elderly cardinal was found with a phone in his pocket after support staff had already exited the chapel. The authors describe the moment as startling, given the layers of security in place. The device was reportedly handed over immediately. There is no suggestion it influenced the outcome of the vote.
