Decius required in 250 that every inhabitant of the empire sacrifice and obtain a certificate saying so — a libellus, signed by a commissioner. Dozens of them survive on papyrus from Egypt, ordinary paperwork naming ordinary people. It was the first persecution that was universal, bureaucratic and indifferent: nobody was hunted, everyone was processed. The church's hardest problem afterwards was not the martyrs but the lapsed, and what to do about those who had merely bought the certificate.
The Rise of Christianity · ch. 10