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Siege and Conquest of Constantinople, 6 April – 29 May 1453

Siege and Conquest of Constantinople, 6 April – 29 May 1453


The walls of Constantinople were a formidable testament to human ingenuity and strength. With towering ramparts and impenetrable fortifications, they stood as a symbol of resilience and defiance. Built to withstand the test of time, they held back armies and preserved the city’s legacy, standing proud and unwavering against the tides of history. But soon, the things were going to change forever.


In the year 1422, Ottoman Sultan Murad II besieged the city of Constantinople. But the walls were too strong for an army without proper siege engines. Meanwhile, a revolt also broke out in Sultan’s realm in Anatolia. Therefore, the Sultan abandoned the siege to deal with the rebels. 

Although Murad could not breach the walls of Constantinople, his victory over the Crusaders first at the Battle of Varna in 1444 and then at the Battle of Kosovo in 1448 proved his supremacy over the Christian powers. With these victories, Sultan also strengthened his holdings in southeastern Europe. But even after these massive victories, the conquest of Constantinople was still a dream for the Ottomans.

When Sultan Murad died, a sigh of relief and happy optimism was felt throughout Europe. The new 19-year-old sultan was unlikely, they thought, to prove a threat to the Christian powers. Murad left a glorious heritage to his successor whose sole aim was to take the city of Constantinople. Therefore, determined to take the city, the 21-year-old Sultan, Mehmed II, later knowns as Mehmed the Conqueror, besieged Constantinople on 6 April 1453.

Preparation for the Siege and Conquest of Constantinople

As soon as Sultan Mehmed II sat on the Ottoman throne, he renewed the old peace treaties and also signed new ones with the Europeans. External as well as internal reasons forced Mehmed to conquer the city as soon as possible. The Byzantine emperor Constantine XI was attempting to stop paying tribute to the Ottoman Sultan and also threatened to support Mehmed’s cousin Orhan in claiming the Ottoman throne. The war was thus inevitable. 

The first step towards the siege came when Sultan ordered the construction of the Rumeli Hisari fortress on the European banks of the Bosphorus. The construction was completed on 31 August 1452. There was already a fortress, known as Anadolu Hisarı, on the Anatolian side of the Bosphorus. It was built by Sultan Bayezid I in 1394 as part of his preparations for the siege of Constantinople.

Throughout the last months of 1452, the Sultan brooded over his plans. He also studied the failures of his predecessors who tried to take the city. Both Anatolian and Rumelian fortresses gave him control of the Bosphorus and enabled him to blockade Constantinople in order to deprive the defenders of any foreign assistance that could come through the sea.

Orban builds a giant cannon

In the summer of 1452, a Hungarian engineer called Orban approached Sultan Mehmed II and offered his services as a maker of artillery for his empire. A huge cannon (The Basilic) was cast at Adrianople by Orban on the orders of Sultan Mehmed.

Ottoman cannons firing at the walls of Constantinople during the Siege and Conquest of Constantinople, 1453

In January 1453, Mehmed ordered a test firing of the gun outside his royal palace. The citizens of Adrianople were warned that there would be a fearful noise and that they must not panic. Indeed, when the fuse was lit and the first ball fired, the reverberation was heard for a hundred stadia, and the ball hurtled through the air for a mile, then buried itself six feet deep in the earth. Mehmed was delighted.

Sultan’s army moves to Constantinople

Once the cannon passed the test, the Sultan ordered it to be sent to Constantinople for the planned siege. On 5 March 1453, the cannon finally set out for Constantinople. 200 men were sent to level the road that led to Constantinople and to strengthen the bridges. The cannon was drawn by 60 oxen with 200 men marching beside it.

Ottoman cannons stationed outside the walls of the Constantinople

Meanwhile, under Orban’s direction, the foundries produced other cannons, though none was to be so huge or so famous as this monster. It took around 4-5 weeks for the guns to join their way to Constantinople.

Throughout the month of March 1453, the Sultan’s great army moved in detachments through Thrace towards the Bosphorus. Sultan Mehmed II himself left the capital (Adrianople) on 23 March. On 5 April he arrived with the last detachments of the army outside the walls of the city.

The Siege of Constantinople begins

The Ottomans under Sultan Mehmed II began the siege of Constantinople on 6 April 1453, but it took a serious turn on 11 April. The Byzantine defences on the sea walls along the Golden Horn were not that much strong when compared to the land walls. Therefore, Mehmed’s goal was to take the Golden Horn and pressure the Byzantines into submission. But the Ottoman fleet led by Baltoghlu could not enter the Golden Horn due to the chain the Byzantines had previously stretched across the entrance.

Ottoman troops during the Siege and Conquest of Constantinople

Baltoghlu was also assigned by the Sultan to prevent any foreign ships from entering the Golden Horn which could provide the supplies to the defenders (Byzantium). But on 20 April, three Genoese galleys sent by Pope Nicholas V managed to slip in after some heavy fighting.

Sultan Mehmed II’s men rolling galleys overland from the Bosphorus behind Pera and Galata to the inner harbour of the Golden Horn

Finding no other way, on 22 April, Mehmed’s men rolled around 70 galleys overland from the Bosphorus behind Pera and Galata to the inner harbour of the Golden Horn. This gigantic engineering feat commenced at dawn with the use of greased planks on the road and sheer manpower. Havoc ensued among the defenders.

On the night of 28 April, an attempt was made to destroy the Ottoman ships already in the Golden Horn using fireships, but the Ottomans forced the Byzantines to retreat with heavy losses.

During the first days of May, Orban’s great cannon had been out of order. But by 6 May it was repaired, and the bombardment of the land walls showed renewed vigour. By 7 May, the siege of Constantinople had completed one month. During these days of the siege, the Ottomans made several frontal assaults on the land wall of Constantinople, but they were always repelled. 

Siege reaches a stalemate

At this point of the siege, a large portion of the Ottoman resources and siege equipment had already been exhausted. There was no guarantee that the siege of Constantinople was going to be successful. But the Sultan was determined and therefore, he continued the siege. The fortune will soon turn in favour of the Sultan.

The Divine signs

There were prophecies popular among the people of Constantinople. According to them, the first Christian Emperor had been Constantine, son of Helena; and the last would also be similarly named.

On 22 May, on the night of the full moon, there was an eclipse and three hours of darkness. The blood moon had lowered the spirits of the defenders even deeper. The next day, as if such omens had not been enough, the whole city was blotted out by a thick fog, a phenomenon unknown in those lands in the month of May.

When these signs of the prophecies appeared, it worsened the morale of the defenders. On the other hand, the Ottomans believed that these were the signs of their victory and soon the True Faith would illuminate the city.

On 26 May, Mehmed summoned his inner Council. Grand Vizier Halil Pasha insisted to abandon the siege. But Zaganos Pasha convinced the Sultan that there can never be a better opportunity to conquer the city if it is not taken today. 

Many of the younger generals rose to support Zaganos; the commander of the Bashi-bazouks was particularly vehement in his demand for stronger action. Mehmed’s spirits rose and this was what he wished to hear. Meanwhile, the news also reached Constantinople to Emperor Constantine XI that no large Venetian relief fleet was on its way. Eventually, Sultan Mehmed would prepare for a final assault.

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The final assault

On 27 May, the Sultan rode through his whole army to announce that the great assault would take place very soon. The Sultan ordered that 28 May, which corresponded to Monday, would be a day of rest and that his warriors should be ready for the final assault on Tuesday (29 May). 

As the sun began to sink towards the western horizon, Sultan prepared his troops for the final assault. At about half-past one in the morning of 29 May, the Sultan gave the order for the assault. All along the line of the walls, the Ottomans rushed into the attack, screaming their battle cries, while drums and trumpets and fifes urged them on. Mehmet himself led the Janissaries into the battle. 

It was just before sunrise that a shot fired at close range struck Giustiniani and pierced his breastplate, which forced him to withdraw from his station at the land wall. Panic spread among Giustiniani’s men. Taking advantage of the loss of morale among the defenders and crying: ‘The city is ours’, Sultan ordered the Janissaries to renew the assault that eventually overwhelmed the Byzantine defences. 

The walls of Constantinople are breached

Suddenly someone looked up and saw the Ottoman flags flying from the tower above the Kerkoporta. The cry went up:

‘The city is taken.’ 

The Sultan himself entered the city in the late afternoon through the Gate of Charisius or Adrianople Gate. After taking the city, Mehmet kept his troops under firm control and did everything he could to keep the city intact so that it could become the centre of his world empire.

Mehmed entering Constantinople

Mehmed rebuilds Constantinople

Mehmed now sought to restore Constantinople (now Istanbul) to its former greatness and to make his capital a microcosm of all the races and religious elements in the empire. As a result, Muslims, Armenians, Jews, Greeks, Slavs, and others came from all parts of the empire.

Grand Bazaar of Istanbul, c. 2008

Many Jews were attracted from as far away as Western Europe, where they were being subjected to a new wave of persecution at this time. Mehmed also began to build the Grand Bazaar, or covered market, which was to become the centre of city’s commercial life for a half-millennium. As a result, within a short time, Constantinople once again flourished.

After its conquest, Sultan Mehmed II established a centralized empire in Europe and Asia with its capital at Constantinople, which was to remain the nucleus of the Ottoman Empire for four centuries. For this marvellous achievement, Mehmed the Conqueror is considered to be the true founder of the Ottoman Empire. 

Photos: Wikimedia


Last updated on May 29th, 2024 at 12:19 pm

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