Answer: The Byzantine Empire finally fell in 1453, after an Ottoman army stormed Constantinople during the reign of Constantine XI
Step-by-step explanation:
The Byzantine Empire fell in 1453. The immediate cause of its fall was pressure by the Ottoman Turks. The Ottomans had been fighting the Byzantines for over 100 years by this time. In 1454, Constantinople finally fell to them and their conquest of the Byzantine Empire was complete.