So I have been getting into Byzantine history lately, and was wondering if the Patriarch during the final fall of Constantinople was killed by the Ottoman's after they took over the city. I know that the current Patriarchs are allowed to live uninterrupted in modern day Istanbul, but was he semi-revered as holy like the Pope was when Rome fell and spared? I know a lot of the Northern Tribes were already converted to Catholicism or the Orthodoxy so they spared them, but was it same for the Ottoman's with the Patriarch even though they were Muslim?
Edit: I really hope someone would still answer this :(
Hi there. Happy to help.
The answer to your question is that there was no Patriarch of Constantinople killed in 1453 because in 1453 there was no Patriarch of Constantinople.
Owing to the attempted reunion of the Churches Konstantinos XI had pursued and the ongoing enforcement of the Council of Florence meant that when Konstantinos died he died without a coronation in Hagia Sophia and with no Patriarch. The last Patriarch before the fall was in fact Gregory III Mammas (1443-1450) who fled to Rome in 1451 because the opposition to Catholicism was so strong he could not enforce nor control the Orthodox clergy. Hence we get the famous line of Loukas Notaras, last grand duke of the city, "Better the sultan's turban than the cardinal's cap."
Some histories of the Siege, refer to Cardinal Isidore, the legate of the Pope, as the Patriarch but the Orthodox Church has not canonised that for obvious reasons. Interestingly, Isidore was not strictly Italian, he had been a servant of Constantinople until 1439 when he was sent to be metropolitan of Kiev, fled to Rome, was made Cardinal by the Pope and was then made legate.