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.

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. The employees took their oaths in the Papal Chapel.