Everyone from cooks to translators to elevator operators took an oath of secrecy at the Vatican on Monday — under threat of automatic excommunication — to prepare for this week’s conclave. Workers and clerics assisting the dozens of Catholic cardinals set to gather Wednesday to begin voting on the next pope had to swear to never reveal anything about the proceedings or else risk the Church’s gravest punishment: religious banishment.

Cleaners and cooks. Doctors and nurses. Even drivers and elevator operators. The support staff for the cardinals who will elect the successor to Pope Francis took an oath of secrecy Monday ahead of the conclave that’s starting on Wednesday.

In an April 29 statement, the Vatican said “the oath of the officials and attendants of the conclave will take place” May 5 in the Pauline Chapel, not far from the Sistine Chapel where the cardinals will vote for the next pope.