1453: The Holy War for Constantinople and the Clash of Islam and the West

by Roger Crowley

The second issue was doctrinal. The bull of excommunication had accused the Eastern Church of omitting one word from the creed – a matter of supreme importance to the theologically preoccupied citizens of Byzantium. The apparently innocuous word, in Latin filioque, “and from the son,” had immense significance. Whereas the original Nicene Creed ran: “I believe … in the Holy Spirit, the Lord, the Giver of Life, who proceeds from the Father, who with the Father and the Son together is worshipped and together glorified,” the Church in the West had come to add the additional word “filioque” to make the text read “who proceeds from the father and from the son.” In time the upshouldering Roman church even started to accuse the Orthodox of error for omitting the phrase. The Orthodox, in reply, claimed that the addition was theologically untrue; that the Holy Spirit proceeds only from the Father, and to add the name of the Son was heretical. Such issues were the stuff of riots within Constantinople.