Theodore first appears as the early companion and friend of Chrysostom, his fellow-townsman, his equal in rank, and but two or three years his senior in age. Together with their common friend Maximus, who was later bishop of
Isaurian Seleucia,
Chrysostom and Theodore attended the lectures of the Greek-speaking teacher of rhetoric
Libanius (Socr. vi.3; Soz. viii.1), then at Antioch in the zenith of his fame. We have the assurance of
Sozomen that he enjoyed a philosophical education. Chrysostom credits his friend with diligent study, but the luxurious life of polite Antioch seems to have received an equal share of his thoughts. When Chrysostom himself had been converted to the
monastic life of
Basil of Caesarea, he likewise converted Maximus and Theodore. The three friends left Libanius and sought a retreat in the monastic school of Carterius and Diodorus, to which Basil was already attached. It is unclear whether Theodore had been previously baptized before taking up monastic vows. Yet from the writings of Chrysostom it is clear he found joy in ascetic self-discipline, and he had just assumed a celibate life when he was fascinated by a girl named Hermione (Chrysostom ibid. i.), and contemplated marriage, at the same time returning to his former manner of life (Soz. viii.2). His "fall" spread consternation through the little society, and the anxiety drew forth from Chrysostom the earliest of his literary compositions - two letters "to Theodore upon his fall." These compositions kept Theodore fast to his vows, although the disappointment left traces in his later life. Chrysostom's connection with
Diodore was probably broken off in 374, when he plunged into a more complete monastic seclusion; Theodore's seems to have continued until the elevation of Diodore to the
see of Tarsus in 378. During this period doubtless the foundations were laid of Theodore's understanding of the
Bible and ecclesiastical doctrine, and he was imbued for life with the principles of scriptural interpretation which Diodore had inherited from an earlier generation of Antiochenes, and with the peculiar views of the Person of Christ into which the master had been led by his antagonism to
Apollinaris of Laodicea. The latter years of this decade witnessed Theodore's first appearance as a writer. He began with a commentary on the
Psalms, in which the method of Diodore was exaggerated, and which he lived to repent of (Facund. iii.6, x.1; v. infra, §III). The orthodox at Antioch, it seems, resented the loss of the traditional Messianic interpretation, and, according to
Hesychius of Jerusalem, Theodore was compelled to promise that he would commit his maiden work to the flames - a promise he contrived to evade (
Mansi, ix.284).
Gennadius of Marseilles (
de Vir. Ill. 12) represents Theodore as a presbyter of the church of Antioch; and from a letter of John of Antioch (Facund. ii.2) we gather that forty-five years elapsed between his ordination and his death. That would mean he was ordained priest at Antioch in 383, in his thirty-third year, the ordaining bishop being doubtless
Flavian, Diodore's old friend and fellow-laborer, whose "loving disciple" Theodore now became (John of Antioch, ap. Facund. l.c.). The epithet seems to imply that Theodore was an adherent of the Meletian party, but there is no evidence that he was involved in the feuds which preoccupied the Catholics of Antioch during Flavian's office. Theodore's great treatise on the Incarnation belongs to this period according to Gennadius, and possibly also more than one of his commentaries on the
Old Testament. As a preacher he seems to have now attained some eminence in the field of polemics (Facund. viii.4). Theodore is said by Hesychius to have left Antioch while yet a priest and remained in Tarsus until 392, when he was consecrated to the see of Mopsuestia on the death of Olympius, probably through the influence of Diodore.
Theodoret states he spent his remaining thirty-six years of life in this town. Mopsuestia was a free town (Pliny) upon the
Pyramus (Ceyhan) river, between Tarsus and
Issus, some forty miles from either, and twelve from the sea. It belonged to
Cilicia Secunda, of which the metropolitan see was
Anazarbus. In the 4th century it was of some importance, famous for its bridge, thrown over the Pyramus by
Constantine I. Theodore's long episcopate was marked by no striking incidents. His letters, long known to the
Assyrians as the
Book of Pearls, are lost; his followers have left us few personal recollections. In 394 he attended a synod at Constantinople on a question which concerned the see of
Bostra in the patriarchate of Antioch. While there, Theodore had the opportunity to preach before the emperor
Theodosius I, who was then starting for his last journey to the West. The sermon made a deep impression, and Theodosius, who had sat at the feet of
Ambrose and
Gregory Nazianzus, declared that he had never met with such a teacher (John of Antioch, ap. Facund. ii.2).
Theodosius II inherited his grandfather's respect for Theodore, and often wrote to him. Another glimpse of Theodore's episcopal life is supplied by a letter of Chrysostom to him from
Cucusus (AD 404–407) (Chrys. Ep. 212). The exiled patriarch "can never forget the love of Theodore, so genuine and warm, so sincere and guileless, a love maintained from early years, and manifested but now." Chrysostom (Ep. 204) thanks him profoundly for frequent though ineffectual efforts to obtain his release, and praises their friendship in such glowing terms that Theodore's enemies at the
fifth Ecumenical Council made unsuccessful efforts to deny the identity of Chrysostom's correspondent with the bishop of Mopsuestia. Notwithstanding his literary activity, Theodore worked zealously for the good of his diocese. The famous letter of Ibas to Maris testifies that he struggled against extinguished
Arianism and other heresies in Mopsuestia. Several of his works are doubtless monuments of these pastoral labors, e.g. the catechetical lectures, the
ecthesis, and possibly the treatise on "Persian Magic." Yet his episcopal work was by no means simply that of a diocesan bishop. Everywhere he was regarded as "the herald of the truth and the doctor of the church"; "even distant churches received instruction from him." So Ibas explained to Maris, and his letter was read without a dissentient voice at the
Council of Chalcedon (Facund. ii.i seq.). Theodore "expounded Scripture in all the churches of the East," says
John of Antioch (ibid. ii.2), with some literary license, and adds that in his lifetime Theodore was never arraigned by any of the orthodox. But in a letter to Nestorius (ibid. x.2) John begs him to retract, urging the example of Theodore, who, when in a sermon at Antioch he had said something which gave great and manifest offence, for the sake of peace and to avoid scandal, after a few days publicly corrected himself. Leontius tells us that the cause of offence was a denial to the
Virgin Mary of the title
Theotokos. So great was the storm that the people threatened to stone the preacher (Cyril of Alexandria Ep. 69). The heretical sects attacked by Theodore showed their resentment in a way less overt, but perhaps more formidable. They tampered with his writings, hoping thus to involve him in heterodox statements (Facund. x.1). Theodore's last years were complicated by two controversies. When in 418 the
Pelagian leaders were deposed and exiled from the West, they sought in the East the sympathy of the chief living representative of the school of Antioch. This fact is recorded by
Marius Mercator, who makes the most of it (
Praef. ad Symb. Theod. Mop. 72). They probably resided with Theodore till 422, when
Julian of Eclanum returned to Italy. Julian's visit was doubtless the occasion upon which Theodore wrote his book
Against the Defenders of Original Sin. Mercator charges Theodore with having turned against Julian as soon as the latter had left Mopsuestia, and anathematized him in a provincial synod. The synod can hardly be a fabrication, since Mercator was a contemporary writer; but it was very possibly convened, as Fritzsche suggests, without any special reference to the Pelagian question. If Theodore then read his ecthesis, the anathema with which that ends might have been represented outside the council as a synodical condemnation of the Pelagian chiefs. Mercator's words, in fact, point to this explanation. A heresiarch greater than Julian visited Mopsuestia in the last year of his life. It is stated by
Evagrius Scholasticus (
H.E. i.2) that
Nestorius, on his way from Antioch to Constantinople (AD 428), took counsel with Theodore and received from him the seeds of heresy which he shortly afterwards scattered with such disastrous results. Evagrius makes this statement on the authority of one Theodulus, a person otherwise unknown. We may safely reject it, so far as it derives the
Christology of Nestorius from this single interview. Towards the close of 428 (Theodoret,
H.E. v.39) Theodore died at the age of seventy-eight, having been all his life engaged in controversy, and more than once in conflict with the popular notions of orthodoxy; yet he departed, as
Facundus (ii.1) triumphantly points out, in the peace of the church and at the height of a great reputation. The storm was gathering, but did not break until after his death. As the Catholic Encyclopedia points out, during his lifetime, Theodore was considered an orthodox Christian thinker. ==Posthumous legacy==