bishop of Rome, was at first a presbyter of the Church of Rome, and afterwards, on the martyrdom of Sixtus II (Eusebius, Hist. Ecclesiastes 7:7; Ecclesiastes 7:27), was chosen bishop of that see A.D. 259, which he held about ten years. He died A.D. 269. Dionysius Alexandrinus (q.v.) was accused before Dionysius of Rome of error as to the person of Christ in his letter to Ammonius and Euphranor, and a synod was called by the bishop of Rome to consider the matter, and an explanation was made by the bishop of Alexandria. The only fragment we have of the writings of Dionysius Romanus relates to this matter; it is a letter to the African bishops, of which Athanasius preserves a large part in his De Decret. Synod. Nic. c. 26; compare also his De Sententia Dionysii, c. 13. It is given also in Migne, Patrol. Latin, tom. 5. See Hefele, Conciliergeschichte, 1:222; Dorner, Doctrine of the Person of Christ, Edinb. transl. 2:182 sq.