The holy Great Martyress Euphemia (the account about her is located under 16 September) suffered martyrdom in the city of Chalcedon in the year 304, during the time of the persecution against Christians by the emperor Diocletian (284-305). One and an half centuries later, at a time when the Christian Church had become victorious within the Roman empire, God deigned that Euphemia the All-Praiseworthy should again be an especial witness and confessor of the purity of the Orthodox teaching.
In the year 451 in the city of Chalcedon, in the very church wherein rested the glorified relics of the holy Great Martyress Euphemia, there took place the sessions of the Fourth Ecumenical Council. The Council was convened for determining the precise dogmatic formulae of the Orthodox Church concerning the nature-composition of the God-Man Jesus Christ. This had been necessitated because of the widely-dispersed heresy of the Monophysites, who opposed the Orthodox teaching about the two natures in Jesus Christ – the Divine and the Human natures [but in one Divine Person as Son of God within the Holy Trinity of three Divine Persons]. The Monophysites falsely affirmed that within Christ was only one nature – the Divine [i.e. that Jesus is God but not man, by nature], causing discord and unrest within the Church. At the Council were present 630 representatives from all the Local Christian Churches. On the side of the Orthodox in the conciliar deliberations there participated Sainted Anatolios, Patriarch of Constantinople, Sainted Juvenalios, Patriarch of Jerusalem, and representatives of Sainted Leo, Pope of Rome. The Monophysites were present in large numbers, headed by Dioscoros, the Alexandrian patriarch, and the Constantinople archimandrite Eutykhios.
After prolonged discussions the two sides could not come to a decisive agreement.
The holy Patriarch of Constantinople Anatolios thereupon proposed that the Council submit the decision of the Church dispute to the Holy Spirit, through His undoubted bearer Saint Euphemia the All-Praiseworthy, whose wonderworking relics had been discovered during the Council’s discussions. The Orthodox hierarchs and their opponents wrote down their confessions of faith on separate scrolls and sealed them with their seals. They opened the tomb of the holy Great Martyress Euphemia and placed both scrolls upon her bosom. Then, in the presence of the emperor Marcian (450-457), the participants of the Council sealed the tomb, putting on it the imperial seal and setting a guard to watch over it for three days. During these days both sides imposed upon themselves strict fast and made intense prayer. After three days the patriarch and the emperor in the presence of the Council opened the tomb with its relics: the scroll with the Orthodox confession was held by Saint Euphemia in her right hand, and the scroll of the heretics lay at her feet. Saint Euphemia, as though alive, raised her hand and gave the scroll to the patriarch. After this miracle many of the hesitant accepted the Orthodox confession, while those remaining obstinant in the heresy were consigned to the Council’s condemnation and excommunication.
After an invasion by the Persians during the seventh century, the relics of Saint Euphemia were transferred from Chalcedon to Constantinople, into a newly built church dedicated in her name. Many years later, during the period of the Iconoclast heresy, the reliquary with the relics of the saint was cast into the sea by order of the Iconoclast emperor Leo the Isaurian (716-741). The reliquary was rescued from the sea by the ship-owning brothers Sergios and Sergonos, who gave it over to the local bishop. The holy bishop ordered that the relics be preserved in secret, beneath a crypt, since the Iconoclast heresy was continuing to rage. A small church was built over the relics, and over the reliquary was put a board with an inscription stating whose relics rested therein. When the Iconoclast heresy was finally condemned at the holy Seventh Ecumenical Council (in the year 787), during the time of Sainted Tarasios, Patriarch of Constantinople (784-806) and the emperor Constantine VI (780-797) and his mother Saint Irene (797-802), the relics of the holy Great Martyress Euphemia were once again solemnly transferred to Constantinople.