He was a slave of Philemon, to whom Saint Paul wrote an Epistle. He ran away from Saint Philemon and met Saint Paul, who sent him back to Saint Philemon, carrying the Epistle. Saint Onesimus was converted to the Catholic Faith by Saint Paul, who baptized him. Later, he became Bishop of Ephesus. Still later, he shed his blood in Rome for the dogmatic truths of the Catholic Faith.