The Fall of Constantinople (1453)

The fall of Constantinople on 29 May 1453 was one of the decisive events of the late Middle Ages. The conquest by the Ottoman sultan Mehmed II ended the Byzantine Empire, which had endured in various forms for more than a thousand years, and it transformed the city of Constantinople into the capital of the Ottoman state. Modern scholarship on the event splits, in ways I find genuinely useful, between Steven Runciman’s view that the fall was the symbolic end of the medieval world, and Roger Crowley’s view (in 1453, 2005) that it was the moment the gunpowder age truly began. The events of 1453 are central to the Ottoman golden age that followed, and the dynasty that conquered the city is traced in the history of the Ottoman Empire.

Key dates

6 April 1453 — Ottoman siege of Constantinople begins.
12 April 1453 — The bombard of Orban opens fire on the walls.
22 April 1453 — The Ottoman fleet enters the Golden Horn over a pontoon bridge.
29 May 1453 — Final assault; the city falls in the early hours of the morning.
6 January 1454 — Mehmed II reinstates the Greek Orthodox patriarch.

The state of the Byzantine Empire in 1453

By the mid-fifteenth century, the Byzantine Empire was a small and impoverished state, reduced to a few square miles around Constantinople, a handful of islands in the Aegean, and the Peloponnese. The last emperor, Constantine XI Palaiologos, had come to the throne in 1449 with the explicit aim of preserving what remained. The empire depended on subsidies from the pope and the Italian maritime republics, on the goodwill of the Ottoman sultan, and on the legendary strength of the Theodosian walls.

The walls of Constantinople, built in the early fifth century by the emperor Theodosius II, had held the city against every assault for nearly a thousand years. They were a triple system: an outer wall, an inner wall, and a moat, defended by 192 towers. The defenders also relied on the small arms, the crossbows, and the artillery of the late medieval period; the famous Greek fire of an earlier age, whose composition had been a state secret of the Byzantine emperors, was no longer available in significant quantities in 1453, although some modern scholars, including John Haldon, argue that limited stockpiles may have survived.

The Ottoman preparation

Mehmed II, who came to the throne in February 1451 at the age of nineteen, was determined to take the city. He spent the first two years of his reign preparing an enormous army, a large fleet, and a massive siege train. The famous bombard cast by the Hungarian engineer Orban, a gun of unprecedented size, required sixty oxen to move and could hurl a stone ball of several hundredweight. The army that converged on the city in April 1453 has been estimated by modern historians at 80,000 to 200,000 men, with the higher figure including irregulars and camp followers. The Ottomans also secured the cooperation of the Greek Orthodox patriarch and the Genoese colony of Pera (Galata) across the Golden Horn. The Genoese agreed to remain neutral, in return for the protection of their commercial interests. The Orthodox population of the city was a major source of information, and many of its members welcomed the prospect of Ottoman rule as a relief from the Latin policies of the dynasty.

The siege

The siege began in early April 1453. The disproportion between the Ottoman army and the defending force, estimated at 7,000 men under Constantine XI and the Genoese captain Giovanni Giustiniani, was overwhelming, but the walls had held off many larger armies, and the defenders were determined. The siege made use of the new gunpowder artillery in ways that had not previously been seen. The bombard cast by Orban fired on the walls from 12 April, but the wall was thick and the gunpowder expensive. The Ottomans also built a pontoon bridge across the Golden Horn to bypass the chain that closed it, an engineering achievement that allowed the army to be resupplied from the north.

The defense was led by the Genoese condottiere Giovanni Giustiniani, who arrived with a small force and took command of the land defenses. The emperor Constantine XI took personal command of the defense of the Mesoteichion, the central section of the wall. The garrison included Catalans, Genoese, Venetians, and the small remnant of the Byzantine army.

The final assault

In the early hours of 29 May 1453, the Ottomans launched their final assault. The attack was made in three waves, and after the first two were repulsed, a third wave, made up of bashi-bazouks, irregulars, found an unguarded entrance through the Kerkoporta, a small postern in the wall. The defense collapsed, and the city was overrun.

Constantine XI died in the fighting, according to tradition, fighting at the gate of St. Romanus. The Doukas and Sphrantzes chronicles both record the emperor’s death on the walls, and the later Turkish tradition, recorded in Tursun Beg’s Tarih-i Ebu’l-Feth, confirms the sultan’s grief at being unable to find the body. The patriarch and many of the notables were taken prisoner. The city was given over to pillage for three days, in accordance with the customary rules of Ottoman siege warfare, and then the sultan entered the city and announced the restoration of order.

The aftermath

The fall of Constantinople had consequences that radiated through the next centuries. The Byzantine Empire was finally extinguished, and the long succession of Greek-speaking states that traced their origin to the Roman Empire of Constantine was at an end. The patriarch was reinstated by Mehmed II on 6 January 1454, and the Orthodox church entered a new phase in which it was led from Istanbul and was the head of the Orthodox world in the Ottoman lands.

The event sent a shock through the Christian world. Pope Nicholas V proclaimed a crusade, and the Portuguese pushed around Africa in search of an alternative route to Asia. The Hagia Sophia, the great church of Byzantine Christianity, was converted into a mosque. The Greek scholars who fled the city in the following decades, taking manuscripts with them, contributed to the Italian Renaissance. For the Ottomans, the conquest was the foundation of their imperial identity. Mehmed II took the title of Caesar and Sultan of the Two Continents. The city, which he renamed Istanbul, was rebuilt as a Muslim capital, with new mosques, palaces, and a population drawn from across the empire. The fall of Constantinople was both an end and a beginning.

Frequently asked questions

How long did the siege of Constantinople last?

Fifty-three days, from 6 April to 29 May 1453. The shorter sieges of 1422 and 1394–1402 had also failed; what made 1453 different was the combination of Orban’s massive bombard, the pontoon bridge across the Golden Horn, and the collapse of the Kerkoporta postern.

Who defended Constantinople in 1453?

The garrison of around 7,000 men was a multinational force: Greek Byzantines under the emperor Constantine XI, the Genoese captain Giovanni Giustiniani, Venetians, Catalans, and a small contingent of papal troops. The civilian population, perhaps 50,000, also took part in the defence.

What happened to the Hagia Sophia after the conquest?

The great church of Byzantine Christianity was converted to a mosque within days of the fall, and the Christian symbols were covered or removed. Mehmed II is said to have spared the building from destruction after a passer-by explained its construction to him, although the story is more pious legend than history. The building remained the principal mosque of Istanbul until the construction of the Süleymaniye in the 1550s.