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...
Crusades; History; Council of Chalcedon (451); Christology; Dioscorus, Patriarch of Alexandria, d. 454; Islam; Jerusalem; Historians; History of the Patriarchs; Patriarchs and patriarchate; Ayyubid dynasty; Fatimid dynasty; Mamluks