When in Rome , the office of Pontifex Maximus was reserved for the emperor , failure to worship him as a god was sometimes punished by death , as the Roman government sought to link emperor worship with loyalty to the Empire . In Rome , the office of Pontifex Maximus came to be reserved for the emperor , who was often declared a ` god ' posthumously , or sometimes during his reign . Failure to worship the emperor as a god was at times punishable by death , as the Roman government sought to link emperor worship with loyalty to the Empire .