Roman Empire; Byzantine Empire; Christianity; Emperors--Byzantine Empire; Diocletian, Emperor of Rome, 245-313; Eusebius, of Caesarea, Bishop of Caesarea, ca. 260- ca. 340; Heresy; Persecution; Arius; Arians; Arianism; Athanasius, Saint, Patriarch...
Patriarchs and patriarchate; Monks; Monasteries; Coptic Church; Ethiopian Orthodox Church; Oriental Orthodox churches; Society and Church; Civil service; Administration; World Council of Churches