Your alternate history challenge create a world where Rome has a French pope. The ottoman empire exists but not in Anatolia. What effects would we see to the Mediterranean and the rest if Europe.
OK how bout we don't have a resurgent Byzantium. How bout Wallachia under Vlad seizes Constantinople and Anatolia and he then goes to war with the kingdom of Epirus.
I know of the timeline but I might add that this Vlad hates the Greeks and wants to create a wallachian empire which will encompass the Byzantines Hungary and Rome itself. Bringing him to war with the French pope.
Well that is up to you.But I would add that this Vlad formed an alliances with the mongols