The brother of John VIII, after two months of heroic defense, he finally fell while facing 150,000 Turkish besiegers directed by Sultan Muhammed II.  
To secure western aid, he proclaimed the unity of the western and eastern fronts, but no help came for his 8000 Greek, Venetian, and Genoese troops.  The brother of John VIII, after two months of heroic defense, he finally fell while facing 150,000 Turkish besiegers directed by Sultan Muhammed II.  FTP, name this defender of Constantinople and last of the Byzantine emperors.
To secure western aid, he proclaimed the unity of the western and eastern fronts, but no help came for his 8000 Greek, Venetian, and Genoese troops.  
Constantine XI