Quick clarification: Are you asking specifically when it was inevitable that the Byzantines would be conquered by the Ottomans, or when it was inevitable that they'd be conquered (by someone)?
Quick clarification: Are you asking specifically when it was inevitable that the Byzantines would be conquered by the Ottomans, or when it was inevitable that they'd be conquered (by someone)?
The OP literally says Ottoman conquest.
Fourth crusade. No, the internal strife just before Fourth CrusadeBy someone
I expressed myself badly, I mean when it was a point that nothing apart from ASB intervention would make the byzantine empire fall, when the empire had no options left and it was terminally condemned to have the eternal faith to be subjulgated by someone else