He seems to have been of an Alexandrian family and was the son of the brother of Theophilus, Patriarch of Alexandria; if he is the Cyril addressed by Isidore of Pelusium in Ep. xxv of Bk. I, he was for a time a monk. He accompanied Theophilus to Constantinople when that bishop held the “Synod of the Oak” in 402 and deposed St. John Chrysostom…