History › Early modern › Ottoman Empire
Fall of Constantinople
May 29, 1453· Battle· Europe
Well documentedSolid records, physical evidence or scientific consensus.
On May 29, 1453, Ottoman Sultan Mehmed II captured Constantinople after a 53-day siege, ending the Byzantine Empire.
See it on the History map →What happened
Mehmed II, aged 21, brought perhaps 50,000 to 80,000 troops against about 7,000 defenders, including Genoese and Venetian volunteers; estimates vary. Giant cannons cast by a Hungarian engineer, Orban, pounded the 1,000-year-old Theodosian Walls, and the Ottomans hauled ships overland to get past a chain across the Golden Horn harbor. The final assault broke through; Emperor Constantine XI died fighting. Mehmed made the city, later called Istanbul, his capital and turned Hagia Sophia into a mosque.
Why it matters
It ended the eastern Roman Empire, made the Ottomans a European great power for centuries, and showed that cannon could defeat the strongest medieval walls.
How we know
Eyewitness accounts survive from both sides, including the Venetian ship's doctor Nicolò Barbaro's diary, the Byzantine official Sphrantzes, and Ottoman chroniclers such as Tursun Beg.
Still debated
Troop numbers vary widely by source; the story that a small gate, the Kerkoporta, was left open and let attackers in rests on one chronicler, Doukas, and may be legend.
Connections (4)
▸Byzantine Empire ended with the Fall of ConstantinopleWell documented
The connection
The eastern Roman Empire, called Byzantine by later historians, had shrunk for centuries: the Fourth Crusade sacked Constantinople in 1204, and by 1450 it held little more than the city and parts of Greece. When the Ottomans took the city in 1453, the last emperor, Constantine XI, died in the fighting, ending a state that traced back to Augustus.
When and how
Constantinople, April 6–May 29, 1453; Emperor Constantine XI Palaiologos against Sultan Mehmed II. The last Byzantine Greek states, the Morea and Trebizond, fell by 1461.
How we know
Byzantine, Italian and Ottoman eyewitness accounts agree on the city's capture and the emperor's death, though not on how he died.
Debates and open questions
How Constantine XI died, and whether more Western help could have saved the city, are debated.
▸Gunpowder breached the walls in the Fall of ConstantinopleWell documented
The connection
Mehmed II hired Orban, a Hungarian cannon-founder, who cast huge bronze bombards; the largest fired stone balls weighing around half a ton. For about six weeks they battered the Theodosian Walls, which had stood since AD 413. Defenders patched the breaches each night, but the bombardment wore them down and opened the gaps where the final assault came.
When and how
Constantinople's land walls, April–May 1453; Mehmed II's artillery, cast at Edirne by Orban, who had first offered his services to the Byzantines.
How we know
Eyewitness accounts from both sides describe the great guns and the damage; surviving Ottoman bombards such as the Dardanelles Gun (1464) show the type.
Debates and open questions
How decisive the cannon were, versus the defenders' small numbers and exhaustion, is debated; the biggest bombard reportedly cracked during the siege.
▸Ottoman Empire triumphed in the Fall of ConstantinopleWell documented
The connection
The Ottomans, a Turkish dynasty from Anatolia, crossed into Europe in the 1350s and surrounded Constantinople, ruling from Edirne. Mehmed II built the Rumeli Hisarı fortress in 1452 to control the Bosphorus, then besieged the city. Victory made Constantinople the Ottoman capital, and Mehmed took the title 'Caesar of Rome'.
When and how
Constantinople, 1452–1453; Sultan Mehmed II, aged 21, with an army of perhaps 50,000–80,000 men; estimates vary.
How we know
Ottoman chronicles, Mehmed's fortress Rumeli Hisarı still standing on the Bosphorus, and his repopulation and rebuilding of the city.
Debates and open questions
Why earlier Ottoman sieges (1394–1402, 1422) failed while Mehmed's succeeded is discussed, as is how seriously he saw himself as Rome's heir.
▸Fall of Constantinople sent Greek scholars to fuel The RenaissanceDebated
The connection
Greek scholars fleeing the Ottomans brought manuscripts and knowledge of ancient Greek to Italy; Cardinal Bessarion gave his library of about 1,000 manuscripts to Venice. But the flow began well before 1453: Manuel Chrysoloras taught Greek in Florence from 1397, and Byzantine delegates attended the Council of Florence in 1438–39. The fall sped up a trend rather than starting it.
When and how
Italy, mainly 1397–1500; Chrysoloras, Bessarion, John Argyropoulos and Constantine Lascaris, who taught Greek in Florence, Rome and Milan.
How sure are we?
Greek manuscripts now in Venice and Florence, and records of Greek teachers in Italian cities, document the scholars' role and its timing.
Debates and open questions
How much 1453 itself mattered is debated: the Renaissance was well underway, and many key Greek texts had arrived decades earlier.