Baring-Gould’s sources: Usuardus, those of SS. Jerome, Bede, &c., the Irish Martyrology of Tamlach, and the Roman Martyrology. Authorities:—Eusebius, lib. viii. c. 6, and the notices in the Martyrologies.

The Emperor Diocletian [Roman emperor 284–305, who began the ‘Great Persecution’ of Christians in 303] having discovered that Peter, one of his officers of the bed-chamber, was a Christian, ordered him to be tortured. Then Gorgonius and Dorotheus, two other officers, filled with indignation, exclaimed, "Why, Sire, dost thou thus torment Peter for what we all profess in our hearts?" The emperor at once ordered them to execution, together with Migdo, a priest, and many other Christians of Nicomedia. Eusebius [Eusebius of Caesarea (d. c. 339), the first historian of the Church] says that Peter was scourged till his bones were laid bare, and that then vinegar and salt was poured over the wounds; and as he bore this without showing anguish, Diocletian ordered him to be broiled on a gridiron slowly, and his flesh, as it roasted, to be taken off slowly, so as to protract his torments. Gorgonius and Dorotheus, after having been tortured, were hung.