DIOSCORUS I. - Patriarch of Alexandria from 444 to 451, died in exile at Gangra in Paphlagonia on 4 December 454. Of Dioscorus's life before he became bishop, it is known only that he was archdeacon of his predecessor St. Cyril, and that he accompanied him to the first Council of Ephesus (431).
From St. Cyril he inherited a great horror of the Nestorian heresy, which went beyond bounds and drove him to attach himself too exclusively to certain christological formulas of his master, which could lend themselves to ambiguity and which were in keeping neither with those of the Antiochene Orientals nor with those of the Latin West. Under the pretext that St. Cyril loved the formula: "One sole incarnate φύσις of the divine Word," he condemned those who maintained that there are in Jesus Christ two natures, δύο φύσεις. From such intransigence, which St. Cyril never knew, all his misfortunes had their origin. When Eutyches, condemned by the Council of Constantinople of 448, appealed to him, he espoused the cause of the obstinate monk, and in agreement with the eunuch Chrysaphius had the emperor Theodosius II convoke an ecumenical council to review his trial. Everything had been arranged beforehand to ensure the rehabilitation of the Constantinopolitan archimandrite, in the conciliabulum that assembled at Ephesus in 449. On the conduct displayed there by Dioscorus, who had secured the presidency of it for himself, v. CALCEDONIA (Il Concilio di C.); EFESO, LATROCINIO di. At Ephesus Eutyches was recognized as orthodox and the "dyophysites" were condemned, that is, those who affirmed the two natures in Christ.
As a consequence of this decision Dioscorus became the father of Monophysitism — not of the crude Monophysitism known under the name of Eutychianism, which made the humanity of the Savior disappear into the divinity, like a drop of water in the ocean, but of verbal Monophysitism, to which Severus of Antioch would later give his name, he who, wholly enslaved to formulas, opposed the terminology canonized by the Council of Chalcedon.
The triumph of Dioscorus after the "Ephesine robbery" was short-lived. In October 451 a new ecumenical council was held at Chalcedon, convoked by the emperor Marcian. Before reaching the city, the Fathers held a preliminary meeting at Nicaea, where Dioscorus, in agreement with some Egyptian bishops, thus excommunicated Pope St. Leo. Such a gesture, along with other misdeeds, was reproached to him at the third session of the Council of Chalcedon (10 October 451), at which he refused to appear, and it procured his deposition. This sentence was approved by the emperor Marcian, who furthermore exiled him to Gangra, where he died.
It seems that Dioscorus wrote little, only a few letters and fragments of letters surviving from him, in Syriac and Armenian translation. A long funeral eulogy by Macarius, bishop of Tkou in Egypt, attributed to him, is not his, or at least has been heavily interpolated. The Memoirs of Dioscorus are also apocryphal, of which fragments remain in Coptic (cf. E. Amélineau, Mémoires publiées par les membres de la mission archéologique française au Caire, IV, Paris 1895, pp. 165-95).
As for the Life of Dioscorus by the deacon Theopistus (F. Nau, Die Vita Dioskurs von Theopistus syrisch und französisch, in Journal asiatique, 10th series, 1 [1930], pp. 5-108, 310-41), it is a dithyrambic eulogy of the protagonist, woven through with legend, which reveals nothing about the life of Dioscorus before his episcopate and which must have undergone later reworkings.