The Fall of Constantinople (Byzantine Greek: Ἅλωσις τῆς Κωνσταντινουπόλεως, romanized: Halōsis tēs Kōnstantinoupoleōs; Turkish: İstanbul'un Fethi, lit. 'Conquest of Istanbul') was the capture of the capital city of the Byzantine Empire by an invading Ottoman army on the Sunday of Pentecost, 29 May 1453. The attackers were commanded by the 21-year-old Sultan Mehmed II, who defeated an army commanded by Emperor Constantine XI Palaiologos and took control of the imperial capital, ending a 53-day siege that had begun on 6 April 1453. After conquering the city, Sultan Mehmed transferred the capital of the Ottoman State from Edirne to Constantinople and established his court there.
The capture of the city (and two other Byzantine splinter territories soon thereafter) marked the end of the Roman Empire, a state which dated to 27 BC, which had lasted for nearly 1,500 years. The conquest of Constantinople also dealt a massive blow to the defence of mainland Europe, as the Muslim Ottoman armies thereafter were left unchecked to advance into Europe without an adversary to their rear.
It was also a watershed moment in military history. Since ancient times, cities had used ramparts and city walls to protect themselves from invaders, and Constantinople's substantial fortifications had been a model followed by cities throughout the Mediterranean region and Europe. The Ottomans ultimately prevailed due to the use of gunpowder (which powered formidable cannons).
The conquest of the city of Constantinople and the end of the Byzantine Empire was a key event in the Late Middle Ages which also marks, for some historians, the end of the Medieval period.
State of the Byzantine Empire
Constantinople had been an imperial capital since its consecration in 330 under Roman emperor Constantine the Great. In the following eleven centuries, the city had been besieged many times but was captured only once: during the Fourth Crusade in 1204.:304 The crusaders established an unstable Latin state in and around Constantinople while the remaining empire splintered into a number of Byzantine successor states, notably Nicaea, Epirus and Trebizond. They fought as allies against the Latin establishments, but also fought among themselves for the Byzantine throne.
The Nicaeans eventually reconquered Constantinople from the Latins in 1261. Thereafter, there was little peace for the much-weakened empire as it fended off successive attacks by the Latins, the Serbians, the Bulgarians, and, most importantly, the Ottoman Turks.The Black Plague between 1346 and 1349 killed almost half of the inhabitants of Constantinople. The city was further depopulated by the general economic and territorial decline of the empire, and by 1453 consisted of a series of walled villages separated by vast fields encircled by the fifth-century Theodosian Walls.
By 1450 the empire was exhausted and had shrunk to a few square kilometres outside the city of Constantinople itself, the Princes' Islands in the Sea of Marmara, and the Peloponnese with its cultural centre at Mystras. The Empire of Trebizond, an independent successor state that formed in the aftermath of the Fourth Crusade, also survived on the coast of the Black Sea.