Catholicos or Patriarch of Armenia (338-439), otherwise known as ISAAC THE GREAT and sometimes as PARTHEV owing to his Parthian origin. He was son of St. Narses and descended from the family of St. Grergory the Illuminator. Left an orphan at a very early age, he received in Constantinople an excellent literary education, particularly in the Eastern languages. After his election as patriarch he devoted himself to the religious and scientific training of his people. Armenia was then passing through a grave crisis. In 387 it had lost its independence and been divided between the Byzantine Empire and Persia; each division had at its head an Armenian but feudatory king. In the Byzantine territory, however, the Armenians were forbidden the use of the Syriac language, until then exclusively used in Divine worship: for this the Greek language was to be substituted, and the country gradually hellenized in the Persian districts, on the contrary, Greek was absolutely prohibited, while Syriac was greatly favoured in this way the ancient culture of the Armenians was in danger of disappearing and national unity was seriously compromised. To save both Isaac invented with the aid of St. Mesrop, the Armenian alphabet and began to translate the Bible; their translation from the Syriac Peshito was revised by means of the Septuagint, and even, it seems, from the Hebrew text (between 410 and 430). The liturgy also, hitherto Syrian was translated into Armenian, drawing at the same time on the Liturgy of St. Basil of Caesarea, so as to obtain for the new service a national colour. Isaac had already established schools for higher education with the aid of disciples whom he had sent to study at Edessa, Melitene, Byzantium, and elsewhere. Through them he now had the principal masterpieces of Greek and Syrian Christian literature translated, e.g. the writings of Athanasius, Cyril of Jerusalem, Basil, the two Gregorys (of Nazianzus and of Nyssa), John Chrysostom, Ephrem, etc.

Armenian literature in its golden age was, therefore, mainly a borrowed literature. Through Isaac's efforts the churches and monasteries destroyed by the Persians were rebuilt, education was cared for in a generous way, the pagan worship of Ormuzd which Shah Yezdigerd tried to set up was cast out, and three councils held to re-establish ecclesiastical discipline. Isaac is said to have been the author of liturgical hymns. Two letters, written by him to Theodosius II and to Atticus of Constantinople, have been preserved. A third letter addressed to St. Proclus of Constantinople was not written by him, but dates from the tenth century. Neither did he have any share, as was wrongly ascribed to him, in the Council of Ephesus (431), though, in consequence of disputes which arose in Armenia between the followers of Nestorius and the disciples of Acacius of Melitene and Rabulas, Isaac and his church did appeal to Constantinople and through St. Proclus obtained the desired explanations. A man of enlightened piety and of very austere life, Isaac owed his deposition by the king in 426 to his great independence of character in 430 he was allowed to resume his patriarchal throne. In his extreme old age he seems to have withdrawn into solitude, dying at the age of 110. Neither the exact year nor the precise month of his death is known, but it seems to have occurred between 439 and 441. Several days are consecrated to his memory in the Armenian Church.

NEUMANN, Versuch einer Gesch. der armen. Literatur, 28-30; MOSES DE CHRENE, in LANGLOIS, Collections des historiens anciens et modernes de l' Armenie, II (Paris, 1869), 159-73; LEQUIEN, Oriens Christianus, I, 1375-7; BARDENHEWER, Patrologie, 549; TER-MI-KELlAN, Die armenische Kirche (Leipzig, 1892), 33-9, FINCK, in Gesch. der. Christl. litteraturen des Orients (Leipzig, 1907), 82-5; Smith, Dict. of Greek and Roman Geography, III, 290.

S. VAILHÉ