The fall of Constantinople is regarded as one of the most famous events in history. This was the key event of Middle-ages and sometimes it is considered as the end of the Medieval Era. It is referred to as the capturing of the Byzantine Empire's Capital (Constantinople) by the Ottoman Empire. Constantinople fell on 29th May 1453 on the day of Sunday. It was a 53 days long siege that started on 6 April 1453 and ended on 29th May 1453.

The City of Constantinople

The Ottoman Army, which was attacking, was led by 21-year-old Sultan Mehmed II with more troops as compared to the defenders of Constantinople, the Byzantine Army (Western-Roman Empire) which was led by Emperor Constantine XI Palaiologos. After Sultan Mehmed II had conquered the city, he changed the city's name to 'Istanbul' and made the city Ottoman's Empire Capital, replacing Adrianople.

The fall of Constantinople marked the end of the Byzantine Empire, actually, the Roman Empire which was founded back in 27 BC. It lasted nearly 1500 years. The myth that circulated in the Byzantine Empire that this city well fell under the ruler of the same name as the founder of the city. This city was founded by Constantine (The first Christian Roman Emperor) and it fell under Constantine XI's rule. Hence the myth came true.


Constantine XI Palaiologos

Many people are confused between the Roman Empire and the Byzantine Empire so let me clear your confusion. In 285 AD, Emperor Diocletian decided that the Roman Empire was too big to manage. He divided the Empire into two parts, the Eastern Roman Empire and the Western Roman Empire. The Western Roman Empire ended in 476 AD under the rule of Emperor Romulus Augustulus. The Eastern Roman Empire became known as the Byzantium Empire and remained in power for another 1000 years and ended in 1453.


Preparations:
When Mehmed II succeeded his father, Sultan Murad II in 1451, he was just 19 years old. Many European courts assumed that this young emperor would not challenge the Christian Empires out there but completely changed thoughts were arising in Mehmed's mind. By early 1452, he started to work on a second fortress which was located seventy miles from Constantinople from the north. The fortress led to Anadolu Hisari Fortress directly by a strait and it was built by Mehmed's Great-Grandfather Bayezid I. The new fortress was named 'Boğazkesen' meaning 'throat-cutter'. In October 1452 Mehmed II ordered 'Turakhan Beg' to station a large garrison force in Peloponnese to block Thomas and Demetrios (kings in Southern Greece) from providing aids to Constantine XI during the forthcoming war. 
The Greek historian Michael Critobulus quotes Mehmed II's speech to his soldiers before the siege:

Sultan Mehmed II

 "My friends and men of my empire! You all know very well that our forefathers secured this kingdom that we now hold at the cost of many struggles and very great dangers and that, having passed it along in succession from their fathers, from father to son, they handed it down to me. For some of the oldest of you were sharers in many of the exploits carried through by them—those at least of you who are of maturer years—and the younger of you have heard of these deeds from your fathers. They are not such very ancient events nor of such a sort as to be forgotten through the lapse of time. Still, the eyewitness of those who have seen testifies better than does the hearing of deeds that happened but yesterday or the day before."

 European help:

Byzantine Emperor Constantine XI quickly perceived Mehmed's true aim and turned to Western Europe for help; but now the price of centuries of war and enmity between the eastern and western churches had to be paid. In the summer of 1452, when Boğazkesen Fortress (The Second Fortress) was completed and the threat of the Ottomans had become at hand, Constantine wrote to the Pope, promising to execute the union, which was declared valid by a half-hearted imperial court on 12 December 1452. Although Constantine XI was confident for the advantage bur Pope Nicholas V didn’t have the influence over the Western Kings and Princes that Byzantines thoughts. Also, the Western Rulers didn’t have the resources to contribute the Byzantines due to previous and ongoing wars in their states. 

However still some troops arrived from Northern Italy but it wasn’t enough for countering Ottomans. In 1452, Cardinal Isidore arrived with 200 archers. In January 1453, an accomplished soldier Giovanni Giustiniani arrived with 400 men from Genoa and 300 men from Chios. As Giustiniani was specialist in defending walled cities so he was immediately given the overall command of defense of land walls by Emperor Constantine XI. Constantine XI also received a letter from Pope Nicholas V who promised to send three ships loaded with resources that will set sail near the end of March. In Venice, the Senate decided to send fleet in February 1453 but it was delayed until April. Furthermore, seven Italian ships with seven hundred men who had sworn to defend Constantinople leaved Constantinople without being noticed. Due to the fear of naval attack by Ottomans along the shores of Golden Horn (a way from sea to enter into Byzantine Territory), Emperor Constantine XI ordered a defensive chain to be placed at the mouth of Golden Horn to prevent any Ottoman Ship entering Golden Horn. This chain gave them hope of extending the siege until the arrival of foreign help. This technique was first used in 1204 when the crusaders attacked Constantinople.  

Strength:

Ottoman Army

Ottoman Strategies: The ottomans had 50000-80000 soldiers including 5000-1000 Janissaries (The Best Soldiers) and 70 cannons. Mehmed II built a fleet of ships to beseige the city from the sea. According to an estimate there were about 110 ships. They had 50-2000 medium sized canons which were made by Turkish Technicians. Orban, A Hungarian mysterious figure initially tried to sell his services to Byzantine Empire but they were short of funds to hire him. Orban then left Constantinople and approached Mehmed II, claiming that his canon would blast the walls of Constantinople easily.  His cannon 'Bascillica' was 27ft long. Given funds and resources he started to make it.


Byzantine Army

Byzantine Strategies: The Byzantines had about 7000 men, out of whom 2000 were foreigners. About 50,000 people were living in the city at that time. The city had about 20km of walls which were in fairly good shape giving the Byzantines reasons to believe that the walls will defend them until the foreign help arrives. It is because the Byzantines didn't know about the large canan 'Bascillica'. They had fleet of 26 ships (from different states)

Attack: 

             Mehmed planned to attack the walls of Constantinople from the west (The only part of the city where it was not surrounded by water). His army encamped outside the city on 2 April, 1453.   On 5th April, The Sultan himself arrive with his last troops and the Byzantine defenders took their positions. As the number of soldiers was less to protect the complete walls, Constantine and his Greek Tropps guarded the middle section of Land Walls because it was the weakest spot and an attack was greatly expected here. Giustiniani was stationed to the north of Constantine. In the south were the Genoese troops. The sea walls were guarded more widely with Jacob Contarini. Greek Monks were to his left hand and Prince Orhan at Eleutherios Harbour. Although the Byzantines also possessed canons but they were much more smaller then the one ottomans had.

Battle of Constantinople, 1453

 At the beginning of the attack, Mehmed sent out his best troops to reduce the Byzantine strongholds outside Constantinople. These were undertakenin few days. During that, Mehmed's massive canon 'Basscillica' fired on the walls but due to its extremely slow rate of reloading, the Byzantines were able to repair most of the damage during that time.

On the other hand, Baltoghlu and his navymen could not enter the Golden Horn due to the chain that Byzantines have stretched across its entrance. Although the main purpose of the chain was to prevent the ship to enter into the Golden Horn but still four Christian ships for help managed to enter Golden Horn after some heavy fight. It upraised the morales of defenders whereas as it caused embarrassment for sultan. Baltoghlu's head was going to be cut off by Sultan for this but his life was spared due to his bravery during the conflict as told by hi subordinates.
 After that Mehmed II ordered the construction of road from greased logs across Galata. They transported ship through the hills (by the road of greased logs) directly into the Golden Horn on 22nd April, bypassing the stretched chain. On the night of 28th April, Byzantines decided to destroy the Ottoman Ships by Fire Ships but they failed as the Governor Lomellini from Byzantine Empire already told Mehmed II Byzantine Emperor's plan. So, Sultan Mehmed II fired cannons onto Fire Ships causing them to destroy and sunk. 40 italians who escaped their ships after sinking hung by Sultan Mehmed II. Governor Lomellini was also hung by Byzantines for deceiving them.

Boats being pushed in Golden Horn

The Ottman army had made many attacks from front but with heavy losses. The Bascillica had also bursted due to its reloading before time resulting in the death of Orban, the canon-maker. 

After these failed frontal attacks, Sultan Mehmed II sent Zaganos Pasha with his miners to break through the walls by constructing tunnels under them. Basically, to weak the bases of walls that would make them fall. However, Byzantine Engineer named 'Johannes Grant' found Ottoman's plan which allowed the Byzantines to enter and kill the miners. The first tunnel was burnt on 16 May. Third tunnel on 23rd May, in which two Turkish men were tortured so they told the location of the tunnels. In this way, all the tunnels were burnt away with people in them. Although Zaganos Pasha survived.

On 21 May, Sultan Mehmed II sent an ambassador to Constantinople and offered that he will stop attacking in return of giving the city to him. He promised that he would allow Emperor Constantine XI and the citizens to leave with their possessions. He also promised the safety of citizens that might choose to live in Constantinople. But Emperor Constantine XI refused because he didn't want to leave the city without a fight.

After the refusal, Mehmed II had a meeting with his Viziers. One of his viziers, Candarli Halil Pasha who always refused the idea of Sultan taking over the Constantinople now gave idea to stop siege and return whereas Zaganos Pasha told the Sultan to attack on last time because now the city's defenses are very much weaker than the past. Mehmed agreed with Zaganos Pasha and started preparations for final all-out attack.

The Final Attack:

The preparations for final attack began in the evening of 26th May and continued for next 36 hours. Prayer and Rest were given to soldiers on 28th before the final assault. On the other hand, more help in the form of 12 ships reached Constantinople from Venice.On 28th May, a solemn ceremony was held in the Hagia Sophia.
After midnight on 29th May, the all-out final attack began. The Christian Troops of the Ottoman Empire were sent for attack first who were followed by azaps, and then Anatolian Turkmen who focused to attack on a weak and damaged wall that was built back in 11th century. They managed to destroy and went through these walls but they were killed by the defenders. Finally the last troop, Janissaries attacked the city walls in which General of Genoese Troops, Giovanni Giustiniani was extremely wounded. His evacuation from the ramparts caused a panic in defenders. The all genoese troops moved way back into the city and towards Golden Horn. Now Constantine XI and his men were left for the war. They eventually couldn't stop Janissaries and finally after seeing one small gate opened, Jannisaries pushed forward. Many Greek Soldiers ran back home for the protection of their family, Venetians ran towards their ship in Golden Horn whereas some escaped to Galata. The rest people either surrendered or committed suicide by jumping off the city walls.


Ottomans inside the city

It is said that either Constantine XI fought the incoming army alone and died or he hanged himself after seeing the Janissaries entering the fate. Although his dead body was never found afterward. Venetians escaped from Golden Horn, although Ottomans were there but they didn't find any good in killing foreign aid. Giustiniani also escaped in the Genoese ships out of the Golden Horn. Ottoman Casulaities (people died or injured in war) are unknown but they are considered very heavy due to many unsuccessful attacks by Ottomans. The blood flowed in the city like rainwater and bodies of Turks and Christians floated in the sea like melons in the canal. The fall of Constantinople put an end to the Roman Empire forever.

Sultan Mehmed II entering into 
Constantinople after victory

Aftermath:

After the victory, Sultan Mehmed II allowed the soldiers for three days to loot the city as he had promised them and in accordance with the custom of time. After three days, Sultan ordered all the soldiers to stop looting and all the citizens who were hidden were allowed to come outside and live in their houses without any question being asked although many homes were destroyed during the loot. The Hagia Sophia was converted into a Mosque. The Fall (I would say rise) of Constantinople shocked numerous europeans and they feared that they would suffer the same fate. Constantinople now Istanbul was declared as the new capital of Ottoman Empire. Sultan Mehmed II declared himself as 'Kayser-i-Rum' meaning 'Caeser of Rome'. Though he was remembered as 'Fatih' meaning 'The Conqueror'.


 

Hagia Sophia now Mosque

Legacy:

1) The Holy Prophet (P.B.U.H) propeheised a hadith about Islamic Conquest of Constantinople:
"Verily you shall conquer Constantinople. What a wonderful leader will he be, and what a wonderful army will that army be!"
2) There are many legends in Greece which tells about the Fall of Constantinople. Like, the partial lunar eclipse that occurred on 22nd May, 1453 predicted the city's demise. Similarly on 26th May, 1453 a strange type of fog was seen above the dome of Hagia Sophia which is interpreted as the leaving of Holy Spirit from the city.