Theodoret, church historian, was born at Antioch about 390, early entered a monastery, and in 423 became Bishop of Cyrus, a city of Syria. Here he laboured with the utmost zeal, and he himself claims to have converted over a thousand Marcionites. As a foremost representative of the school of Antioch he became deeply involved in the great Nestorian and Eutychian controversies, and was finally deposed by the celebrated Robber-council of Ephesus in 449. This was reversed by the general council of Chalcedon in 451, but Theodoret did not long survive his restoration, dying about 457.
His works were edited by Schulze and Nüsselt (Halle, 1769-74), and consist of commentaries on Canticles, the Prophets, Psalms, and the whole of St Paul's Epistles; a History of the Church, from 325 to 429 A.D., in five books, ed. by T. Gaisford (1854), trans., with Evagrius (1851); Religious History, being the lives of the so-called Fathers of the Desert, a series of most curious and interesting pictures of early ascetic life; the Eranistes, a dialogue against Eutychianism; A Concise History of Heresies, together with orations and nearly 200 letters. See Binder, Études sur Théodoret (Geneva, 1844); Specht, Theodor von Mopsuestia und Theodoret von Cyrus (Mun. 1871); Roos, De Theodoreto Clementis et Eusebii compilatore (Halle, 1883); and A. Bertram, Theodoreti Doctrina Christologica (Hildesheim, 1883).