Amorium was a bishopric at latest by 431, when its bishop, Abraham or Ablabius, was at the Council of Ephesus. The acts of the earlier First Council of Constantinople (381) were signed by a priest, Tyrannus, of Amorium. Other bishops were Mysterius, who took part in the Council of Chalcedon in 451, Theodorus, in the Trullan Council of 692, Theodosius, in the Second Council of Nicaea in 787, and Bessarion in the Council of Constantinople (879). Theophilus was part of the mission that Photius sent to Rome about 20 years earlier.