of Christians. 248 Origen writes in Against Celsus that the Roman empire is a Divine Will . 249-251 Persecution under Emperor Decius . 250 Hieromartyr Fabian , Bp. of Rome; martyrdom of Pionius of Smyrna . 257-260 Persecution under Emperor Valerian (253-260). 257 Hieromartyr Stephen , Bp. of Rome, and those