The heart of the tension was a theological one. The Orthodox were firm on their creed and we will come to see how they refused any compromise with the Latin West. Even at the pleas of the Byzantine Emperor and the presence of the Ottomans at the walls, the Orthodox clergy refused to bend to the doctrine of the West. They knew the Ottomans, despite being of a foreign religion, would require no such theological compromise.

XREF: Connects to general historical dynamics where religious doctrine trumps pragmatic political alliance, echoing patterns seen in other religious schisms.

Ali Qureshi, The Fall of Constantinople, loc. 24