ܐܦܛܪܘܦܘܬܐ ܦܛܪܝܪܟܝܬܐ
 ܕܡܪܥܝܬܐ ܕܐܘܚܕ̈ܢܐ ܡܥܪ̈ܒܝܐ ܕܐܡܝܪܟܐ

Sometimes surnamed the Great, was a bishop and patriarch of Antioch in the 324-337. He was a native of Side in Pamphylia in (270?). About 320 he was bishop of Beroea (Aleppo), and he became patriarch of Antioch in 323/4 before the council of Nicaea in 325, died in exile at Trajanopolis in Thrace, most probably in 336/7, according to some in 360.

At the Council of Nicæa (325), since he was presiding the council, he distinguished himself zealously against the Arians and was one of the most prominent opponents of Arianism, and from 325-330 he was engaged in an almost continuous literary warfare against the Arians. By his fearless denunciation of Arianism and his refusal to engage any Arian priests in his diocese, he incurred the hatred of the Arians, who, headed by Eusebius of Cæsarea and his namesake of Nicomedia, held a synod at Antioch (331) at which Eustathius was accused, by suborned witnesses, of Sabellianism, incontinency, cruelty, and other crimes. He was deposed by the synod and banished to Trajanopolis in Thrace by order of the Emperor Constantine, who gave credence to the scandalous tales spread about Eustathius. The people of Antioch, who loved and revered their holy and learned patriarch, became indignant at the injustice done to him and were ready to take up arms in his defense. But Eustathius kept them in check, exhorted them to remain true to the orthodox faith and humbly left for his place of exile, accompanied by a large body of his clergy. The adherents of Eustathius at Antioch formed a separate community by the name of Eustathians and refused to acknowledge the bishops set over them by the Arians (After transferring St Eustathius to exile, the Arians took control of the See of Antioch and appointed the following Patriarchs: Eulalius 331-333, Euphornius 333-334, Philaclus 334-342, Stephanos 342-344, Leontius 344-357, Eudoxius 358-359, Euzoios 360). When, after the death of Eustathius (336/7), St. Meletius became Bishop of Antioch in 360 by the united vote of the Arians and the orthodox, the Eustathians would not recognize him, even after his election was approved by the Synod. Their intransigent attitude gave rise to two factions among the orthodox, the so-called Meletian Schism, which lasted till the second decade of the fifth century.

Most of the numerous dogmatic and exegetical treatises of St. Eustathius have been lost. His principal extant work is "De Engastrimytho", in which he maintains against Origen that the apparition of Samuel (I Kings, xxviii) was not a reality but a mere phantasm called up in the brain of Saul by the witch of Endor. In the same work he severely criticizes Origen for his allegorical interpretation of the Bible. His feast is celebrated in the Latin Church on 16 July, in the Orthodox on 21 Feb. His relics were brought to Antioch.

The only complete work by Eustathius is the De Engastrimytho contra Origenem (ed. by A. Jahn in Texte und Untersuchungen, ii. 4). Other fragments are enumerated by G. F. Loofs in ''Herzog-Hauck s Realencyklop die''.