Fall of Constantinople

The Fall of Constantinople refers to the siege and capture of the Byzantine capital on 29 May 1453 by Ottoman forces commanded by Sultan Mehmed II ("the Conqueror"). After roughly 53 days of siege, Ottoman troops breached the Theodosian Walls, the triple land fortifications that had protected the city since the 5th century. The last Byzantine emperor, Constantine XI Palaiologos, died defending the city; his exact fate is not recorded with certainty.

The siege is often treated as a turning point in military history because of the prominent use of large bombards, including cannon reportedly cast by the Hungarian engineer Orban, which were able to damage walls that had withstood earlier sieges. The Ottomans also famously transported ships overland to bypass the chain across the Golden Horn, neutralising the city's naval defences.

For international-relations students, the event matters for several reasons:

• It ended the Byzantine Empire, the institutional continuation of the Eastern Roman state, and removed the last major Christian power in Anatolia and the southern Balkans.
• It transformed Constantinople (later commonly called Istanbul) into the capital of the Ottoman Empire, which would dominate southeastern Europe, the Levant, and North Africa for centuries.
• It disrupted established overland trade routes between Europe and Asia, a factor traditionally cited as a contributor to European interest in alternative maritime routes and the Age of Exploration, though historians debate how direct that causal link was.
• It accelerated the westward movement of Greek scholars and manuscripts, often associated with the later phases of the Italian Renaissance.

In some periodisations, 1453 is used as a conventional marker for the end of the Middle Ages, alongside other 15th-century events. The Hagia Sophia, the city's principal cathedral, was converted into a mosque shortly after the conquest.