Eulogius was first igumen of the monastery of the Mother of God in Antioch.

[3][4] Eulogius refuted the Novatians, some communities of which ancient sect still existed in his diocese, and vindicated the hypostatic union of the two natures in Christ, against both Nestorius and Eutyches.

Cardinal Baronius says that Gregory wished Eulogius to survive him, recognizing in him the voice of truth.

[2] It has been said that he restored for a brief period to the Church of Alexandria life and youthful vigour.

[3] Besides the above works and a commentary against various sects of Monophysites (Severans, Theodosians, Cainites and Acephali) he left eleven discourses in defence of Pope Leo I and the Council of Chalcedon, also a work against the Agnoetae, submitted by him before publication to Pope Gregory I, who after some observations authorized it unchanged.