The Fall of Constantinople (Greek: Άλωση της Κωνσταντινούπολης, Alōsē tēs Kōnstantinoupolēs; Turkish: İstanbul'un Fethi Conquest of Istanbul) was the capture of Constantinople, the capital of the Eastern Roman (Byzantine) Empire, which occurred after a siege by the invading Ottoman Empire, under the command of 21-year-old Ottoman Sultan Mehmed II, against the defending army commanded by Byzantine Emperor Constantine XI Palaiologos. The siege lasted from Friday, 6 April 1453 until Tuesday, 29 May 1453 (according to the Julian calendar then in general use), when the city fell and was finally conquered by the Ottomans.
The capture of Constantinople (and two other Byzantine splinter territories soon thereafter) marked the end of the Roman Empire, an imperial state which had lasted for nearly 1,500 years. The Ottoman conquest of Constantinople also dealt a massive blow to Christendom, as the Ottoman armies thereafter were free to advance into Europe without an adversary to their rear. After the conquest, Sultan Mehmed transferred the capital of the Ottoman Empire from Adrianople to Constantinople. Several Greek and non-Greek intellectuals fled the city before and after the siege, with the majority of them migrating particularly to Italy, which helped fuel the Renaissance.
The conquest of the city of Constantinople and the end of the Byzantine Empire marks, for some historians, the end of the Middle Ages.
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