IRENAEUS (b. c. 13o), bishop of Lyons at the end of the 2nd century, was one of the most distinguished theologians of the ante-Nicene Church. Very little is known of his early history. His childhood was spent in Asia Minor, probably at or near Smyrna; for he says (Adv. hoer. iii. 3, 4, and Euseb. Hist. Eccl. v. 2o) that as a child he heard the preaching of Polycarp, the aged bishop of Smyrna (d. 156). He can hardly have been born very long after 13o, for later on he frequently mentions having met certain Christian presbyters who had actually seen John, the disciple of our Lord. At the time of the persecution of the Gallic Church under Marcus Aurelius (177) he was a presbyter of the church at Lyons. In 177 or 178 he went to Rome on a mission from this church, to make representations to Bishop Eleutherius in favour of a more lenient treatment of the Mon tanists. (See MONTANISM; Eus. v. 4. 2.) On his return to Lyons Irenaeus was called upon to replace Bishop Pothinus, who had perished in the persecution (Eus. v. 5. 8). As bishop he carried on a great and fruitful work. Though the statement of Gregory of Tours (Hist. Franc. 1. 29), that within a short time he succeeded in converting all Lyons to Christianity, is probably exaggerated, from him at any rate aates the wide spread of Christianity in Lyons and its neighbourhood. He sought to reconcile the numerous sects which menaced the existence of the church. In the dispute on the question of Easter, he endeavoured to effect a compromise, and in particular to exer cise a moderating influence on Victor, the bishop of Rome, and his unyielding attitude towards the dissentient churches of Africa, thus justifying his name of "peace-maker" (Eirenaios) (Eus. H.E. v. 24. 28). The date of his death is unknown. His martyr dom under Septimius Severus is related by Gregory of Tours, but by no earlier writer.
The chief work of Irenaeus, written about 18o, is his "Refuta tion and Overthrow of Gnosis, falsely so called" (usually in dicated by the name Against the Heresies). Of the Greek original of this work only fragments survive; it only exists in full in an old Latin translation. The treatise is divided into five books : of these the first two contain a description and criticism of the tenets of various heretical sects, especially the Valentinians; the other three set forth the true doctrines of Christianity. His work is the first systematic exposition of Catholic belief. The foun dation upon which Irenaeus bases his system consists in the episcopate, the canon of the Old and New Testaments, and the rule of faith. With their assistance he sets forth and upholds, in opposition to the gnostic dualism, i.e., the severing of the natural and the supernatural, the Catholic monism, i.e., the unity of the life of faith as willed by God. The "grace of truth" (the cha risma), which the apostles had called down upon their first dis ciples by prayer and laying-on of hands, and which was to be imparted anew by way of succession (6caaoxi, succession) to the bishops from generation to generation without a break, makes those who receive it living witnesses of the salvation offered to the faithful by written and spoken tradition. The Scriptures of the Old and New Testaments, rightly expounded by the church alone, give us an insight into God's plan of salvation for man kind, and explain to us the covenant which He made on various occasions (Moses and Christ ; or Noah, Abraham, Moses and Christ). Finally, the "rule of faith" (regula fidei), received at
baptism, contains in itself all the riches of Christian truth.
This exposition by Irenaeus of the divine economy and the in carnation was taken as a criterion by ldter theologians, especi ally in the Greek Church. (Cf. Athanasius, Gregory of Nyssa, Cyril of Alexandria, John of Damascus.) He himself was espe cially influenced by St. John and St. Paul. Before him the Fourth Gospel did not seem to exist for the Church; Irenaeus made it a living force. His conception of the Logos is not that of the philosophers and apologists; he looks upon the Logos not as the "reason" of God, but as the "voice" with which the Father speaks in the revelation to mankind, as did the writer of the Fourth Gospel. And the Pauline epistles are adopted almost bodily by Irenaeus, according to the ideas contained in them; his exposi tions often present the appearance of a patchwork of St. Paul's ideas. Certainly, it is only one side of Paul's thought that he displays to us. The great conceptions of justification and atone ment are hardly ever touched by Irenaeus.
Till recent times whatever other writings and letters of Irenaeus are mentioned by Eusebius appeared to be lost, with the excep tion of a fragment here or there. Two Armenian scholars, Karapet Ter-Mekerttschian and Erwand Ter-Minassianz, published from an Armenian translation a German edition (Leipzig, 1907 minor edition 1908) of the work "in proof of the apostolic teaching" mentioned by Eusebius (H.E. v. 26). This work, which is in the form of a dialogue with one Marcianus, otherwise unknown to us, contains a statement of the fundamental truths of Christianity. It is the oldest catechism extant, and an excellent example of how Bishop Irenaeus was able not only to defend Christianity as a theologian and expound it theoretically, but also to preach it to laymen.
BIBLIocRAPHy.—The edition of the Benedictine R. Massuet (Paris, 1710 and 1734, reprinted in Migne, Cursus patrologiae, Series Graeca, vol. v., Paris, 1857) long continued to be the standard one, till it was superseded by the editions of Adolph Stieren (2 vols., Leipzig, 1848-53) and of W. Wigan Harvey (2 vols., Cambridge, 1857), the latter being the only edition which contains the Syriac fragments. For an English translation see the Library. Of modern monographs con sult H. Ziegler, Irenaeus, der Bischof von Lyon (1871) ; Friedrich Loofs, (Leipzig, 1888) ; Johannes Werner, Der Paulinismus des Irenaeus (Leipzig, 1889) ; Johannes Kunze, Die Gottes lehre des Irenaeus (Leipzig, 1891) ; Ernst Klebba, Die Anthropologie des heiligen Irenaeus (Munster, 1894) ; Albert Dufourcq, Saint Irenee (Paris, 1904) ; Franz Stoll, Die Lehre des hell. Irenaeus von der Erlosung and Heiligung (Mainz, 19o5) ; also the histories of dogma, especially Harnack, and Bethune-Baker, An Introduction to the Early History of Christian Doctrine (19°3) ; Bonwetsch, Die Theologie des Irenaeus (1925).