THEODORET, bishop of Cyrus, and an important writer in the domains of exegesis, dogmatic theology, church history, and ascetic theology, was born in Antioch, Syria, about 390. At an early age he entered the cloister ; and in 423 he became bishop of Cyrus, or Cyrrhus, a small city between Antioch and the Euphrates; where, except for a short period of exile, he spent all the rest of his life. The date of his death is uncertain, but it must have been at least six or seven years later than the council of Chalcedon (451). Although thoroughly devoted to the ideals of nionasticism, he discharged his episcopal duties with remarkable zeal and fidelity. He was diligent in the cure of souls, labouring bard and successfully for the conversion of the numerous Gnostic communities and other heretical sects which still maintained a footing within the diocese. He himself claims to have brought more than a thousand Marcionites within the pale of the church, and to have destroyed many copies of the Diatessarom of Tatian, which were still in ecclesiastical use ; and he also exerted himself to improve the diocese, which was at once large and poor, by building bridges and aqueducts, beautifying the town, and similar works.

As an exegete Theodoret belongs to the Antiochene school, of which Diodorus of Tarsus and Theodore of Mopsnestia were the heads. He was not actually the personal disciple of either, but he adopted their methods, though without the consistency and boldness of the first-named. His extant commentaries (those on Canticles, on the Prophets, on the book of Psalms, and on the Pauline epistles - the last the most valuable) are among the best performances of the fathers of the'church. They are brief, yet not wanting in that element of practical edification on which Chrysostom lays special weight as characteristic of the Antiochenes. In addition to these complete commentaries, we have fragments of some others (of that on Isaiah, for example), principally met with in catenw. There are also special elucidations of some difficult Scripture texts.

Theodoret's chief importance is as a dogmatic theologian, it having fallen to his lot to take part in the great monophysite- Nestorian controversy and to be the most considerable opponent of the view of Cyril and Dioscurus of Alexandria. For more than twenty years he maintained the struggle against the Alexandrian dogmatic and its formulre (Beal-Orrin, EYGICTIS Har inrocrracriv, 14(a ihr4d-raa-ts, gvtudts shudrIch, and the like), and taught that in the person of Christ we must strictly distinguish two natures (hypostases), which are united indeed in one person (prosopon), but are not amalgamated in essence. For these years his history coincides with that of the Eastern Church from 430 to 451, and for this very reason it is impossible to sketch it even briefly here (see Hefele, Cone.- _ gesch., vol. ii.). The issue was not unfavourable to Theodoret's cause, but melancholy enough for Theodoret himself : the council of Chalcedon condemned monophysitism indeed, but he unhappily yielded to pressure so far as also to take part in pronouncing "anathema upon Nestorius, and upon all who call not the Holy Virgin Mother of God, and who divide the one Son into two." As Theodoret had previously been a constant defender of Nestorius, it was impossible for him to concur in this sentence upon his unfortunate friend with a clear conscience, and in point of fact he did not change his own dogmatic position. It is distressing, therefore, to find him in his subsequent Epitome classing Nestorius as a heretic, and speaking of him with the utmost hostility. Some of Theodoret's dogmatic works are no longer extant : of his five books Hepi evavOpaiwhaews, for example, directed against Cyril after the council of Ephesus, we now possess fragments merely. A good deal of what passes under his name has been wrongly attributed to bins. Certainly genuine are the refutation ('Avarpori)) of Cyril's twelve klateepaTicritof of Nestorius, and the 'Epayecrrns, or riax6/4opoes (written about 446), consisting of three dialogues, entitled respectively'Al-pesrres, 'Acrsfyxwros, and 'Airctehs, in which the monophysitism of Cyril is opposed, and its Apollinarian character insisted on. Among the apologetico-dogmatic works of Theodoret must be reckoned his ten discourses Ilepl wpovofas.

Theodoret gives a valuable exposition of his own dogmatic in the fifth book of his Alpe-J-1)6s Nalco/A.01as 47rtrom4, already referred to.' This, the latest of his works in the domain of church history (it was written after 451), is a source of great though not of primary importance for the history of the old heresies. In spite of the investigations of Volkmar and Hilgenfeld, we are still somewhat in the dark as to the authorities he used. The chief uncertainty is as to whether he knew Justin's Syntagma, and also as to whether he had access to the Philosophumena of Hippolytus in their complete form. Besides this work Theodoret has also left us a church history in five books, from 324 to 429, which was published shortly before the council of Chalcedon. The style is better than that of Socrates and Sozomen, as Photius has remarked, but as a contribution to history the work is inferior in importance. It is probable that its author was acquainted with the labours of Socrates ; he appears also to have used those of Philostorgius the Arian, but not those of Sozomen. Something indeed still remains to be cleared up as to the sources he employed ; apart, however, from some documents he has preserved, relating to the Arian controversy, he does not contribute much that is not to be met with in Socrates. lie made a thorough study of the writings of Athanasius for the work. As regards chronology be is not very trustworthy; on the other hand, his moderation towards opponents, not excepting Cyril, deserves recognition. The 'ExAnvitc&iv OepcoreuriK4 ircavacircup (De Curanclis Gravorum Affeetionibus) - written before 438 - is of an historical and apologetic character, very largely indebted to Clement of Alexandria and Eusebins; it aims at showing the advantages of Christianity as compared with Hellenism, and deals with the assaults of pagan adversaries. The superiority of the Christian faith both philosophically and ethically is set forth, the chief stress being laid on monachism, with which heathen philosophy has nothing to compare. Much prominence is also given to the cult of saints and martyrs.

On this side of his character, however, Theodoret can best be studied in the thirty ascetic biographies of his Sotaleor Icrropia. This collection, which has been widely read, is a pendant to the Historic Lausiaea of Palladino and the monkish tales of Sozomen. For the East it has had the same importance as the similar writings of Jerome, Sulpicius, Severus, and Cassianus for the West. It shows that the "sobriety" of the Antiochene scholars can be predicated only of their exegesis; their style of piety was as exaggerated in its devotion to the ideals of monasticism as was that of their monophysite opponents. Indeed, one of the oldest leaders of the school, Diodorus of Tarsus, was himself among the strictest ascetics.

Nearly 200 letters of Theodoret have come down to us, partly in a separate collection, partly in the Ada of the councils, and partly in the Latin of Marius Mercator ; they are of great value not only for the biography of the writer but also for the history of his diocese and of the church in general.

The edition of Slrmond (Paris, 1642) was afterwards completed by Gamier (1684), who has also written dissertations on the author's works. Schulze and Nosselt published a new edition (6 vols., Halle, 1769-74) based on that of their predecessors; a glossary was afterwards added by Bauer. The reprint will be found In vols. lxxx.-lxxxlv. of Nigne, and considerable portions occur in Mansi. Besides the earlier labours of Tillemont, Ceillier. Oudin, Du Pin, and Eabrielus and Harless, see Schriiekli, Kirchengesch., vol. xvill.; Hefcle, Conc.-gesch., vol. 11.; Richter, De Theodoreto Epp. Paul. Interprete, Leipsic, 1822; Binder, Etudes sur Theodora, Geneva, 1844; Stiludlin, desch. u. Lit. der Kirchengesch., Ilanovcr.1827; Kihn, Die Bedeutung der antioch. Schule, 1866; Diestel, Des A. 7'. in der christt. Kirche, Jena, 1889; Specht, Theodor v. dlopsvestia u. Theodoret v. Cyrus, Munich, 1971 ; Roos, De Theodoreto Clententis et Eusebti Compilatore, Halle. 1883; Jeep, Quellenuntersuch. r. d. griech. Ktrchenhistortkern, Leipsic, 1834; and Miller, art. "Theodorct," In Herzog-Plitt's Realencykl., vol. xv. (A. HA.)