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.

The Vatican also plans to use signal jamming during the conclave to prevent electronic surveillance or communication outside the conclave, with the Vatican gendarmes overseeing the security measures. The provisions for the oath-taking are laid down in Vatican law.

Support staff for the cardinals who will elect Pope Francis' successor are taking an oath of secrecy on Monday before the conclave starts on Wednesday.