At Chalcedon, opposite Constantinople on the Bosporus, the relics of Euphemia – a supposed Christian martyr of the Diocletianic Persecution – were housed in a martyrium accompanied by a basilica. The basilica already existed when Egeria passed through Chalcedon in 384, and in 436 Melania the Younger visited the church on her own journey to the Holy Land. From the description of Evagrius Scholasticus the church is identifiable as an aisled basilica attached to the martyrium and preceded by an atrium.Evagrius Scholasticus, Ecclesiastical History, II.3: "The precinct consists of three huge structures: one is open-air, adorned with a long court and columns on all sides, and another in turn after this is almost alike in breadth and length and columns but differing only in the roof above." The Council of Chalcedon (8–31 October 451) was held in the basilica, which must have been large enough to accommodate the more than two hundred bishops that attended its third session, together with their translators and servants; around 350 bishops attended the Council in all. In an ekphrasis in his eleventh sermon, Asterius of Amasea described an icon in the church depicting Euphemia's martyrdom. The church was restored under the patronage of the patricia and daughter of Olybrius, Anicia Juliana. Pope Vigilius fled there from Constantinople during the Three-Chapter Controversy. The basilica, which lay outside the walls of Chalcedon, was destroyed by the Persians in the Byzantine–Sasanian War of 602–628 during one of the Sasanian occupations of the city in 615 and 626. The relics of Euphemia were reportedly translated to a new Church of St Euphemia in Constantinople in 680, though Cyril Mango argued the translation never took place. Subsequently, Asterius's sermon On the Martyrdom of St Euphemia was advanced as an argument for iconodulism at the Second Council of Nicaea in 787.
At Chalcedon opposite Constantinople on the Bosporus the relics of Euphemia – a supposed Christian martyr of the Diocletianic Persecution – were housed in a martyrium accompanied by a basilica The basilica already existed when Egeria passed through Chalcedon in 384 and in 436 Melania the Younger visited the church on her own journey to the Holy Land From the description of Evagrius Scholasticus the church is identifiable as an aisled basilica attached to the martyrium and preceded by an atriumEvagrius Scholasticus Ecclesiastical History II3 "The precinct consists of three huge structures one is open-air adorned with a long court and columns on all sides and another in turn after this is almost alike in breadth and length and columns but differing only in the roof above" The Council of Chalcedon (8–31 October 451) was held in the basilica which must have been large enough to accommodate the more than two hundred bishops that attended its third session together with their translators and servants; around 350 bishops attended the Council in all In an ekphrasis in his eleventh sermon Asterius of Amasea described an icon in the church depicting Euphemia's martyrdom The church was restored under the patronage of the patricia and daughter of Olybrius Anicia Juliana Pope Vigilius fled there from Constantinople during the Three-Chapter Controversy The basilica which lay outside the walls of Chalcedon was destroyed by the Persians in the Byzantine–Sasanian War of 602–628 during one of the Sasanian occupations of the city in 615 and 626 The relics of Euphemia were reportedly translated to a new Church of St Euphemia in Constantinople in 680 though Cyril Mango argued the translation never took place Subsequently Asterius's sermon On the Martyrdom of St Euphemia was advanced as an argument for iconodulism at the Second Council of Nicaea in 787