Martyrs  Anicetus and Photius of Nicomedia:  after several miraculous events during their tortures, they bodies were not consumed by the fire the were thrown into which led to the conversion of many pagan witnesses.  Overall the Roman persecutors may have been better evangelists than many Christians in bringing people to the Faith.

http://oca.org/saints/lives/2015/08/12/102279-martyr-anicetus-of-nicomedia

http://images.oca.org/icons/sm/august/0812anicletus.jpg