AD 324: Constantine moves the capital of the Roman Empire to Byzantium

The new capital of the Roman Empire was inaugurated in 324 AD at ancient Byzantium, by Emperor Constantine The Great, after whom it was named, and dedicated on 11th May 330.

AD 325: New walls are built

Constantine’s fortifications consisted of a single wall, reinforced with towers at regular distances.

AD 378: Battle of Adrianople

On August 9th, A.D. 378, Valens was killed and his army lost to an army of Goths led by Fritigern, whom Valens had given permission only two years earlier to settle in Roman territory.

AD 405: Anthemius begins the Theodosian Walls

AD 408: Accession of Theodosius II

AD 423: Completion of the Theodosian Walls

AD 447: Much of the walls destroyed by earthquakes

AD 626: Siege by the Persians and Avars

The siege failed because the Avars did not have the patience or technology to conquer the city. The walls of Constantinople easily defended against the siege towers and engines. Furthermore, the Persians and Slavs did not have a strong enough navy to counter the sea walls and establish a channel of communication. The Avars’ lack of supplies eventually caused them to abandon the siege

AD 627: Building of the Wall of Heraclius

In the northwestern corner of the city, the suburb of Blachernae with its important church of “Panagia Blacherniotissa” was left out of the Theodosian walls. To defend it, in the face of the great Avar siege, a single wall was built.

AD 674: Siege by the Arabs begins

Arab fleets secured bases along the coasts of Asia Minor, and then proceeded to install a loose blockade around Constantinople. They used the peninsula of Cyzicus near the city as a base to spend the winter, and returned every spring to launch attacks against the city’s fortifications.

AD 678: Use of Greek fire ends the Arab siege

Finally, the Byzantines, under Emperor Constantine IV, managed to destroy the Arab navy using a new invention, the liquid incendiary substance known as Greek Fire. The Byzantines typically used it in naval battles to great effect, as it could continue burning while floating on water. These, however, were different mixtures and not the Byzantine formula, which was a closely guarded state secret, a secret that has now been lost.

AD 714: Second siege by the Arabs

A combined assault, from the land and the sea. An 80,000 strong army led by Maslama, crossed the Bosporus from Anatolia to besiege Constantinople by land, while a massive fleet of Arab war galleys, estimated to initially number 1,800, sailed into the Sea of Marmara to the south of the city. Emperor Leo III was able to use the famed Walls of Constantinople to his advantage and the Arab army was unable to breach them, whilst the Arab galleys were unable to sail up the Bosporus as they were under constant attack and harassment by the Greek fleet, using Greek fire to great effect.

AD813: Leo V adds outer wall in Blachernae Quarter. Siege by Krum the Bulgarian.

Leo V the Armenian built a new wall in front of the Heraclean wall to safeguard against Bulgarian raids.
AD 860: Siege by the Russians

According to the Patriarch Photius, an eyewitness to the events, the Russian attack of AD 860 was swift and absolutely unexpected ‘as a swarm of wasps’. The Russians had picked their moment well, because the emperor and his army were fighting the Arabs in Asia Minor, and the fleet was absent fighting the Arabs and Normans in the Aegean and Mediterranean. This exceptional double advantage by both land and sea suggests that the Russians may have been informed of the situation, especially the absence of the fleet. The land defense of the capital was also weakened, because the imperial army that was fighting against the Arabs consisted not only of the troops stationed in Asia Minor but also of those regiments that were usually stationed in the neighbourhoods of the capital and could therefore most easily rally to its defense. The coasts of the Black Sea, the Bosphorus, and the Sea of Marmara, including its islands, were almost defenseless and helplessly exposed to Russian attacks. In any event, deliverance from the Russian threat was once more attributed to the intercession of the Virgin Mary. Having hurried back to the capital, the emperor took the relic of the robe of the Virgin Mary from the church at Blachernae. It was paraded round the walls and then symbolically dipped into the sea. Immediately after this was done a strong wind arose and the ships of the ‘godless Russians’ were wrecked.

AD 1071: Battle of Manzikert

The Battle of Manzikert (Turkish: Malazgirt Muharebesi) was a fight between the Byzantine Empire and the Seljuq Turks on August 26, 1071 near Manzikert. The decisive defeat of the Byzantine army and the capture of the Emperor Romanos IV Diogenes played an important role in undermining Byzantine authority in Anatolia and Armenia, and allowed for the gradual ‘Turkification’ of Anatolia.

AD 1081: Alexius Comnenus enters Constantinople

Alexios was able to halt the Byzantine decline and begin the military, financial, and territorial recovery known as the Komnenian restoration.

AD 1097: First Crusade threatens Constantinople

The frustrated soldiers of the First Crusade who had to pass by the great, and to them mysterious, city on their way to the Holy Land made an assault on the walls of Constantinople. While negotiations with the crafty Alexius Comnenus were proceeding, the envoys of the crusaders were on one occasion detained so long by the emperor as to arouse suspicions of treachery on his part. A band of crusaders rushed from the camp, and in their attempt to enter the city and rescue their comrades set fire to the Gate of Blachernae.

AD 1204: Fourth Crusade takes Constantinople

Tragedy struck the walls of Constantinople when more crusaders returned a century later. The notorious Fourth Crusade of AD 1204 was the only occasion prior to the fall of the city to the Ottomans in AD 1453 that the walls were breached. The Fourth Crusade had originally been designed to conquer Egypt, but after the failure of the Third Crusade there was little interest in Europe for another crusade against Islam. The Fourth Crusade, summoned by Pope Innocent III in AD 1198, was the last of the major crusades to be directed by the papacy. The later crusades were directed by individual monarchs, and even the Fourth quickly fell out of papal control. The Crusaders were reluctant to attack fellow Christians, but the clergy convinced them that the Orthodox Byzantines were the next best thing to the Muslims.

Twenty warships, the pathetic remains of the Byzantine navy, were sunk and the weight of the crusaders’ navy broke the massive chain across the Golden Horn. Siege positions were taken up on the hill overlooking the Blachernae quarter.

The assault was made with catapults and scaling ladders from ships in the Golden Horn.

The crusaders captured the Blachernae area and used it as a base to attack the rest of the city, but while attempting to defend themselves with a wall of fire, they ended up burning down even more of the city than they had the first time. Eventually, the crusaders were victorious, and inflicted a horrible and savage sacking on Constantinople for three days, during which many ancient works of art were stolen or destroyed.

The Latin Empire, established by the Crusaders in Constantinople, had poor control over former Byzantine territory, and Byzantine successor states sprang up in Epirus, Trebizond, and Nicaea.

In 1204, Byzantine emperor Alexios V Ducas Murtzouphlos fled Constantinople after crusaders invaded the city. Theodore I Lascaris, the son-in-law of Emperor Alexios III Angelos, was proclaimed emperor, but he too fled, to the city of Nicaea (today İznik) in Bithynia, realizing the situation in Constantinople was hopeless.

AD 1261: Constantinople “recaptured” from the Latins

Michael VIII Palaiologos recovered Constantinople from the Latin Empire in 1261 and transformed the Empire of Nicaea into a “restored Byzantine Empire”. In 1260, Michael began the assault on Constantinople itself, which his predecessors had been unable to do. He allied with Genoa, and his general Alexios Strategopoulos spent months observing Constantinople in order to plan his attack. In July 1261, as most of the Latin army was fighting elsewhere, Alexius was able to convince the guards to open the gates of the city. Once inside he burned the Venetian quarter (as Venice was an enemy of Genoa, and had been largely responsible for the capture of the city in 1204).

AD 1345: Extensive repairs carried out to walls

The Theodosian Walls were injured once more by the great earthquake of October 1344, Inner and Outer walls were repaired from one end of the line to the other, and the parapet along the Moat was raised to the height of a man; making this the most extensive restoration of the Theodosian Walls since 447.

AD 1422: Siege by Murad II

The first full-scale Ottoman Siege of Constantinople took place in 1422 as a result of the Byzantine Emperor Manuel II’s attempts to interfere in the succession of Ottoman Sultans, after the death of Mehmed I in 1421. This policy of the Byzantines was often used successfully in weakening their neighbours. When Murad II emerged as the winning successor to his father, he marched into Byzantine territory. For the first time, the Turks had acquired their own cannons by the siege of 1422, “falcons”, which were short but wide cannons. The two sides were evenly matched technologically, and the Turks had to build barricades “in order to receive… the stones of the bombards.”

The Byzantine defenders won the battle.
AD 1453: Constantinople falls to Mehmet the Conqueror (according to Nicolo Barbaro5)

Preparation for the conquest of Constantinople started in 1452. Huge canons6 that were necessary for the great siege were molded at Rumeli Castle, Hungary. On the European side, to control the Bosphorus, a mighty fleet of 16 galleys was formed, the number of soldiers were doubled, the supply routes to Byzantine were taken under control, and finally an agreement was made with the Genoese to keep Galata neutral during the war. In April 1453, the first Ottoman frontier forces were seen in front of the city, the siege was starting:

6th April 1453

Sultan Mehmed pitched his imperial tent by the door of St. Romanus in the Topkapi neighborhood. The same day the city was besieged by land from the Golden Horn to the Marmara Sea.

6-7th April 1453

First cannons fired. Some of the fortresses in Edirnekapi neighborhood were destroyed.

9th April 1453

Baltaoglu Suleyman Bey launched the first attack to enter the Golden Horn inlet.

9-10th April 1453

Some of the fortresses on the Bosphorus were taken. Baltaoglu Süleyman Bey seized the Marmara Islands.

11th April 1453

The city walls were bombarded by cannon fires. Holes and cracks began to appear, with eventual, serious destruction inflicted by the ceaseless bombardment.

12th April 1453

The Ottoman fleet attacked the ships protecting the Golden Horn. The victory of the Christian ships decreased the morale of the Ottoman army. At the order of Sultan Mehmed, the Byzantine ships were pounded by mortar fire, and one galley was sunk.

18th April 1453, Night

The Sultan gave his first crucial order. The attack lasted four hours but it was scattered.

20th April 1453

A naval skirmish took place close to Yenikapi neighborhood between the Ottoman fleet and four Byzantine warships with three supply ships full of food and weapons sent by the Papacy. The Sultan came to the shore himself and ordered Baltaoglu Süleyman Pasha to sink those ships by any means possible. The Ottoman fleet could not stop the enemy’s ships. With this failure, the Ottoman army lost its morale and showed signs of defeat. Ottoman soldiers started defecting from the army. Soon, the Byzantine Emperor wanted to take advantage of this situation and offered peace. The offer was supported by the Vizier Çandarli Halil Pasha, but was rejected by Sultan Mehmed. The siege and bombardment of the fortresses with cannons continued. During this chaos and widespread feeling of defeat, a letter from the Sultan’s spiritual teacher Aksemseddin promised good news about the conquest. Encouraged by this spiritual support, Fatih Sultan Mehmed escalated the attack and decided to add an element of surprise: the Ottoman fleet, anchored in Dolmabahçe bay, would be moved to the Golden Horn by land.

22th April 1453

In the early hours of the morning, Byzantines were shocked and horrified when they saw Ottoman galleys moving down on the hills of the harbor. Seventy ships carried by cows and balanced by hundreds of soldiers via ropes were slid over slipways. By the afternoon, the ships were inside the well protected bay. The surprise appearance of the Ottoman fleet in the bay created panic among the Byzantine residents of Constantinople. The wall on the shore of the Golden Horn became a vulnerable spot and some of the Byzantine forces were moved there. This weakened the defense of the land walls.

7th May 1453

A three hour long attack was launched on the stream of Bayrampasa with a 30,000 strong force, however it failed.

12th May 1453

A thunderous attack made towards the point between Tekfur Palace and Edirnekapi was defeated by the Byzantine defense.

16th May 1453

Where the underground tunnel dug in the direction of Egrikapi intersected the Byzantine underground tunnel, an underground skirmish erupted. The same day, an attempt to cut the big chain blocking the entrance of the Golden Horn failed. The following day the attack was repeated, but again ended in failure.

18th May 1453

Ottoman forces launched another attack from the direction of the Topkapi neighborhood by using a mobile wooden tower. The Byzantines burned the tower at night and emptied the trenches that were filled by the Ottomans. Over the following days, the bombardment of the land walls continued.

25th May 1453

Fatih Sultan Mehmed, sent Isfendiyar Beyoglu Ismail Bey as an ambassador offering the Emperor the option of surrender for the last time. According to this offer, the Emperor and his followers could take their wealth and go anywhere they wished. The people who decided to stay could keep their belongings and estates. This offer was rejected.

27th May 1453

The order for a general attack was announced to the Ottoman army.

28th May 1453

The army spent the day resting and preparing for the following day’s attack. There was a complete silence among soldiers. Sultan Mehmed inspected the army and encouraged them for the great attack. On the other side, a religious ceremony was held at the Hagia Sophia Church. The Emperor urged people to participate in the defense of the city. This would be the last Byzantine ceremony.

29th May 1453

Mehmet II conquered Constantinople. Sultan Mehmed gave the order to attack at midnight. Inside Constantinople, while the soldiers positioned for war, people filled the churches. The Ottoman army launched its final assault. The first assault was carried out by infantry and was followed by Anatolian soldiers. When 300 Anatolian soldiers were killed, the Janissaries started their attack. With the presence of Sultan Mehmed, the Ottoman army was motivated and hand to hand fights started. A young soldier, Ulubatli Hasan, who first erected the Ottoman flag on the Byzantine land wall, was martyred. Upon the advance of the Janissaries from the Belgradkapi neighborhood and the surrender of the last defenders at the Edirnekapi front, the Byzantine defense collapsed.

The Emperor was killed during street skirmishes. Turkish forces entered from every direction and crushed the Byzantine defense completely. Towards noon Sultan Mehmed entered the city. He went directly to the Haghia Sophia Church and ordered its conversion into a mosque.



The Dardanelles Gun : is a siege gun dating from soon after the fall of Constantinople in 1453. It is cast in bronze and was made in two parts: the barrel which holds the shot and the chamber which holds the charge. The two parts screw together and there is a ring of sockets at the ends of each section, these take levers to facilitate screwing and unscrewing the parts. Overall length is 5.2 m and it weighs 16.8 tonnes. It fires a stone ball of about 300 kg some 1600 m. The rate of fire was very slow – about 15 rounds per day. Currently in the Royal Armouries at Fort Nelson, Portsmouth, England.

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GENERAL CHRONOLOGY OF THE SIEGE AD 324: Constantine moves the capital of the Roman Empire to Byzantium The new capital of the Roman Empire was inaugurated in 324 AD at ancient Byzantium, by Emperor Constantine The Great, after whom it was named, and dedicated on 11th May 330. AD 325: New walls...