3. Of ANTIOCH, an ecclesiastical writer who lived during the latter part of the fourth century after Christ, and belonged to a noble family. During the time that he was a presbyter and archimandrita at Antioch, he exerted himself much in introducing a better discipline among the monks, and also wrote several works, which shewed that he was a man of extensive acquirements. When Meletius, the bishop of Antioch, was sent into exile in the reign of the emperor Valens, Diodorus too had to suffer for a time; but he continued to exert himself in what he thought the good cause, and frequently preached to his flock in the open fields in the neighbourhood of Antioch. In A. D. 378 Meletius was allowed to return to his see, and one of his first acts was to make Diodorus bishop of Tarsus. In A. D. 381 Diodorus attended the council of Constantinople, at which the general superintendence of the Eastern churches was entrusted to him and Pelagius of Laodiceia. (Socrat. 5.8.) How long he held his bishopric, and in what year he died, are questions which cannot be answered with certainty, though his death appears to have occurred previous to A. D. 394, in which year his successor, Phalereus, was present at a council at Constantinople. Diodorus was a man of great learning (Facund. 4.2); but some of his writings were not considered quite orthodox, and are said to have favoured the views which were afterwards promulgated by his disciple, Nestorius. His style is praised by Photius (Bibl. Cod. 223, where he is called Theodorus) for its purity and simplicity. Respecting his life, see Tillemont, Hist. des Emp. viii. p. 558, &c., and p. 802, &c., ed. Paris.

Diodorus was the author of a numerous series of works, all of which are now lost, at least in their original language, for many are said to be still extant in Syriac versions. The following deserve to be noticed : 1. Κατὰ εἱμαρμένης in 8 books or 53 chapters, was written against the theories of the astrologers, heretics, Bardesanes, and others. The whole work is said to be still extant in Syriac, and considerable Excerpta from it are preserved in Photius. (l.c.) 2. A work against Photinus, Malchion, Sabellius, Marcellus, and Ancyranus. (Theodoret. de Haeret. Fab. ii. in fin.) 3. A work against the Pagans and their idols (Facund. 4.2), which is perhaps the same as the Κατὰ Πλάτωνος περὶ Δεοῦ καὶ Δεῶν. (Hieronym. Catal. 119.) 4. Χρονικὸν διορθούμενον τὸ σφάλμα Εὐσεβίου τοῦ Παμφίλον περὶ τῶν χρόνων, that is, on chronological errors committed by Eusebius. (Suid. s. v. Διόδωρος.) 5. Περὶ τοῦ εἷς Θεὸς ἐν Τριάδι, was directed against the Arians or Eunomians, and is said to be still extant in Syriac. 6. Πρὸς Γρατιανὸν κεφάλαια. (Facund. 4.2.) 7. Περὶ τῆς Ἱππάρχου σφαίρας. This Hipparchus is the Bithynian of whom Pliny (Plin. Nat. 2.26) speaks. 8. Περὶ προνοίας, or on Providence, is said to exist still in Syriac. 9. Πρὸς Εὐφρόνιον φιλόσοφον, in the form of a dialogue. (Basil. Epist. 167 ; Facund. 4.2.) 10. Κατὰ Μανιχαίων, in 24 books, of which some account is given by Photius. (Bibl. Cod. 85; comp. Theodoret. i. in fin.) The work is believed to be extant in Syriac. 11. Περὶ τοῦ ἁγίου πνεύματος. (Phot. Bibl. Cod. 102; Leontius, do Sectis, pp. 448.) 12. Πρὸς τοὺς Συνονσιαστάς, a work directed against the Apollinaristae. Some fragments of the first book are preserved in Leontius. (Bibl. Patr. ix. p. 704, ed. Lugdun.) This work, which is still extant in Syriac, seems to have been the principal cause of Diodorus being looked upon as heretical; for the Nestorians appealed to it in support of their tenets, and Cyrillus wrote against it. 13. A commentary on most of the books of the Old and New Testament. This was one of his principal works, and in his interpretation of the Scriptures he rejected the allegorical explanation, and adhered to the literal meaning of the text. (Suidas, l.c. ; Socrat. 6.2 ; Sozomen. 8.2; Hieronym. Catal. 119.) The work is frequently referred to by ecclesiastical writers, and many fragments of it have thus been preserved. (Cave, Hist. Lit. i. p. 217, ed. London ; Fabric. Bibl. Gr. iv. p. 380, ix. p. 277, &c.)