Siege of Constantinople Ends: Byzantine Capital Falls to Ottoman Turks

 by Siggurdsson

"Siege of Constantinople" by Philippe de Mazarolle c. 1453-1475
From the Chronique de Charles VII by Jean Chartier
Currently located at the National Library of France, Paris
(Unless otherwise indicated, all illustrations are courtesy of Wikipedia)

May 29, 1453
Today's signature event is considered by many scholars and historians as the end of the Middle Ages. It is also regarded as the final, defining end of the Roman Empire.

Background
Since its founding in 330 by Roman Emperor Constantine the Great, Constantinople was considered the "second Rome." After the decline and fall of the Western Roman Empire in the late fifth century, the Eastern Empire acquired the political, social, and religious mantle of its predecessor. In the early sixth century, the Byzantine Empire controlled large portions of land that were once part-and-parcel of the original Roman Empire. However, several wars with the Sassanid Persian Empire, the migrations of various barbarian tribes, and the rise of the followers of Islam all contributed to the East Roman Empire's contraction.
However, the capture of the city by western European forces in 1204 signaled the beginning of the end of the "Great City.",and by the mid-fifteenth century, the Byzantine Empire had shrunk to an area that encompassed the area immediately around the capital city, the southernmost portion of the Greek peninsula, and a few islands in the Aegean Sea (see the map below). The only real allies – military and economic – the Romans had were the Italian maritime cities of Genoa and Venice.

Map of eastern Mediterranean c. 1450 (Byzantine possessions in purple)

In the late fourteenth century, the rise of the Ottoman Turks presented the single greatest threat to the continuation of the Byzantine kingdom. The accession of Mehmed II as Turkish sultan in 1451 was initially not believed to threaten Constantinople. Only 19 years of age, he assured Byzantine ambassadors that he did not present a real threat to them. However, he was determined to final bring down the "Great City" once and for all. To that end, Mehmed began preparations to accomplish this goal.
In April of 1452, Mehmed ordered the construction of a fortified castle across the Bosphorus northeast of the Byzantine capital. With up to 1000 mason working constantly, the new stronghold was constructed in a little over four-and-a-half months, under the personal supervision of the new sultan. This Turkish fortification was called Rumelihisari, and was a companion to Anadoluhisari, a strongpoint established on the Asian side of the strait by Mehmed's grandfather. The two castles consequently controlled the sea lanes to Constantinople, effectively blocking any avenues for relief by sea to the city.
[The newer Ottoman fort was originally named Boğzkesen, which can be translated as either "strait-blocker" or "throat-cutter," to indicate its important strategic position.]
Rumelihisari was garrisoned by 400 Janissaries (the sultan's elite bodyguards) and a number of large cannon were place in one of its three main towers. Shortly after the fortress was fully garrisoned, a Venetian merchant ship entered the Bosphorus from the Black Sea. When signaled to stop for inspection, the vessel ignored the command. Artillery from Rumelihisari bombarded and sank the ship, and 20 surviving crewmen were beheaded on the beach. This incident was a stark demonstration that the Byzantine capital was in grave peril.

Rumelihisari today, outside Istanbul, Turkey

Constantinople and Its Defenses
The city known variously as the "New Rome," the "Great City," Konstantiniyye, Tsarigrad, and Miklagard had once held a population estimated at between 500,000 and 800,000 inhabitants in the 9th and 10th centuries. The capture of the city in 1204 by Crusaders and the Black Death of 1347 greatly depopulated the city. By 1450 there were only about 50,000 people in the city, including thousands of refugees from neighboring areas that had been forced out of their homes by the Turks. In fact, one source describes Constantinople as a series of villages within the city's walls.
In its 1100+ year existence, Constantinople had withstood a number of sieges. In nearly every case the stout walls, brave defenders, and intrepid Byzantine navy had broken armies of Arabs, Avars, Bulgars, Persians, and Rus'. The Ottoman Turks had attempted three sieges previously, in 1390-1402, 1411, and 1422. The city was literally a walled fortress; in addition to the Theodosian walls guarding the western side of Constantinople, every single foot of the city's shoreline was lined with strong fortifications. These extensive walls totaled some 20 kilometers.

Computer recreation of the Theodosian Walls, showing moat in foreground
[Photograph courtesy of http://www.maquetland.com]

With the loss of its traditional recruiting grounds in the Balkans, Greece, and Asia Minor, the Byzantines began to rely more heavily upon hiring mercenary units. The garrison of Miklagard totaled about 7000 soldiers, of which 2000 were foreigners. [One sellsword unit of note inside the city was a Turkish contingent, hired directly by the Emperor Constantine XI, kept their oath of allegiance, dying to a man in the siege's final days.] The small size of the garrison forced the Byzantines initially to defend only the Theodosian Walls. There were a few reserve forces in other locations of the city. The defenders also had a number of cannon to defend the city.
Another vital link in the defenses of the Great City was the floating chain which extended from the city itself across the Golden Horn to the suburb of Galata (which had grown up around a stronghold built specifically to guard the chain). This chain, which floated on wooden logs, was strong enough to prevent any Turkish ship from entering the harbor. Using a series of winches, the chain could be loosened to allow ships to enter the Golden Horn.

Remains of Golden Horn chain today, on display in the Istanbul Military Museum, Turkey
[Photograph courtesy of http://www.maquetland.com]

The Byzantine navy, though well-trained and well-equipped, was composed of 26 ships – 10 Byzantine and the remainder from Genoa, Pisa, and other Western nations. In addition, a force of Genoese and Pisan sailors was assigned the defense of the Italian quarter, an area of the city inhabited mainly by Italian merchants and sailors across the Golden Horn from Galata.
Ottoman Turk Forces
Mehmed II was determined to capture Konstantiniyye at almost any cost. He gathered men from his entire domain, his army eventually totaling between 50,000 and 80,000 Ottoman soldiers. This number included between 5000 and 10,000 Janissaries, the sultan's bodyguards who were former Christian slaves converted to Islam and highly trained as elite warriors. The army also included thousands of Christian troops from nearby conquered regions, including some 1500 Serbians under their despot Đurađ Branković. Almost certainly there were subject troops from Hungary, Bulgaria, and Wallachia (modern-day Romania) in the Turkish force as well.
One of the advantages which the Turks enjoyed was a number of cannon that would be used to batter the walls of Constantinople. One the sultan's most valuable assets was a Hungarian (or possibly German) engineer named Orban. He had offered his services to the Byzantines, but they did not have sufficient funds to employ him. Once in Mehmed's employ, he began construction of a bronze cannon the likes of which the world had never seen before.
This colossal artillery piece – christened "Basilica" – was over 27 feet long, 30 inches in diameter, and had walls 8 inches thick to absorb the extreme force of the huge gunpowder loads. It fired stone balls weighing between 600 and 1500 pounds up to a mile. It became the centerpiece of the sultan's strategy to batter down the walls of Constantinople. It required sixty oxen and 400 men to transport the gun from its foundry Adrianople the 140 miles to Constantinople, and took six weeks to reach Constantinople.
In addition to this giant marvel, Orban and his men cast at least 69 smaller cannon to "batter the very walls of Babylon" (according to Orban himself). There were also some cannon with a barrel length of up to 14 feet, not quite as imposing as the "Basilica," but still formidable. A number of other large siege weapons – including trebuchets – were also constructed and transported to the Byzantine capital.

Artist's conception of Turkish super-cannon "Basilica" during siege of Constantinople
[Image courtesy of http://www.flickriver.com/photos/cool-art/4483317597/]

The Ottoman naval force was equally formidable, consisting of about 126 ships, including a number of large and small fighting galleys, rowing boats and 20 horse transports.

"Mehmed II Conquering Constantinople" by Fausto Zonaro (1903)
Ottoman army on the march (note giant bombard on right); Mehmed on white horse on left
Oil on canvas, currently at the Dolmabahçe Palace, Istanbul, Turkey
(Unless otherwise indicated, all illustrations are courtesy of Wikipedia)

Today in Military History: May 29, 1453
Prelude to the Battle
Emperor Constantine XI knew his capital was in dire trouble when the Rumelihisari was under construction. He sent a number of pleas to every major ruler in western Europe, asking for help. European response was mostly negative. Both England and France had recently exhausted themselves in the Hundred Years' War; Spain was still deeply involved in the Reconquista; Poland and Hungary were still licking their wounds after their defeat by the Turks during the Varna campaign of 1444; and there was internecine warfare within the German domains. Catholic pontiff Nicholas V offered aid, if the Orthodox Church would submit to Papal authority. Seeking any avenue of assistance Constantine agreed, which netted him a mere 200 archers. [Many Byzantines were disgusted by the emperor's deal, saying they preferred Turkish domination to Roman.]
While no nation offered substantial aid, certain individuals did come to defend Constantinople. The most notable was Giovanni Guistiniani, a young and capable Genoese commander. He brought a force of 700 Italian and Greek soldiers from the island Chios to Constantinople in January of 1453. Guistiniani had personally financed, organized and led this expedition on his own initiative, and upon arrival he was placed in command of the land defenses by the emperor. He was critical in getting the various Italian merchant factions to cooperate and coordinate their efforts. Unfortunately, at the moment of Guistiniani's arrival, seven Italian ships with 700 men slipped away from the city.
In late March, Turkish forces began their march to vicinity of Miklagard. Their progress was slowed by the portage of the colossal artillery piece "Basilica." The sultan's army arrived before the walls of Constantinople on Easter Monday, April 2, 1453, with Mehmed himself coming on the scene on April 5.
Siege of Constantinople
After spending a few days to take their positions, the Ottoman siege of Constantinople began on April 6. The bulk of the Ottoman army was encamped south of the Golden Horn. The regular European troops, stretched out along the entire length of the walls, were commanded by Karadja Pasha. The regular troops from Anatolia under Ishak Pasha were stationed south of the Lycus River down to the Sea of Marmara. Mehmed himself erected his red-and-gold tent near the Mesoteichion, where the guns and the elite regiments, the Janissaries, were positioned. The bashi-bazouks, irregular troops with poor reputations, were spread out behind the front lines. Other troops under Zaganos Pasha, the second vizier of the Ottomans, were employed north of the Golden Horn. A bridge of boats was constructed over the marshy ground at the end of the Golden Horn to allow for quicker communication.

Initial Ottoman dispositions at start of siege of Constantinople
(Sorry, I could not find an English version of this map, hope you can read French)

The Ottoman artillery was grouped in 14 or 15 batteries of three to five guns each. Orban's monster cannon was set up in front of the sultan's tent, so he could monitor its operations personally. Turkish sappers had preceded the main force, and had cut down orchards and vineyards outside the Theodosian Walls to provide a clear field of fire. Others dug a ditch the length of the walls and 250 yards from them, with an earth rampart to shield the guns.
With less than 7000 men to cover 12 miles of fortifications, Emperor Constantine ordered the bulk of his army to concentrate on defending the western walls. Several groups of reserve troops were stationed in other parts of the city.
Meanwhile, after weeks of work to set up the huge cannon and protect it, on April 12 the entire Ottoman artillery park was put to work. Every cannon roared to life, and modern history's first artillery barrage began. An eyewitness to the first firing of the "Basilica" later stated:

…there was first a terrifying roar and a violent shaking of the ground beneath and for a great distance around, and a din such as has never been heard. Then, with a monstrous thundering and an awful explosion and a flame that illuminated everything round about and scorched it, the wooden wad was forced out by the hot blast of dry air and propelled the stone ball powerfully out. Projected with incredible force and power, the stone struck the wall, which it immediately shook and demolished, and it was itself shattered into many fragments, and the pieces were hurled everywhere, dealing death to those standing nearby.

The huge stone cannonballs struck the Byzantine walls with tremendous force. It had a deleterious effect on the defenders' morale. Sailors on ships in the Golden Horn felt the concussion of the "Basilica" from miles away. Defenders tried to hang cotton bales, leather sheets, even precious church tapestries in front of the walls to cushion the effect of the barrage, all to no effect.
However, the huge gun had one big drawback: it took nearly three hours to reload, limiting itself to only seven shots a day. The tremendous heat of each detonation threatened to widen micro-fissures in the bronze barrel. After each firing, "Basilica" was coated in warm olive oil to prevent cold air from further damaging the weapon. After six weeks, the barrel of the super-cannon cracked, killing and wounding a number of its crew. Sultan Mehmed ordered the gun repaired by putting metal hoops around the barrel to hold it together. Shortly afterwards, the gun exploded and its supporting platform collapsed, effectively removing it from the siege.
After six straight days of bombardment, Mehmed ordered a massive assault on the Theodosian walls. It was a spectacular failure, with great loss of life on the Ottoman side. The initial attacks were spearheaded by the Christian subject troops, with some of the elite Janissaries also thrown into the mix. Unfortunately for the Turks, the Byzantine defenders fought with ferocious courage. The city's defenders had organized work gangs which worked every night to repair the fortified walls, using wooden stakes, pieces of the shattered walls, and any other material to keep the Turks out. This went on throughout the siege. In addition, the Greeks used cannon of their own, though they were small calibers than the Turkish pieces.
While the land engagements continued, the Turkish navy was engaged in two main jobs: penetrating the Golden Horn to attack the Byzantine fleet, and keeping any reinforcements from reaching the city by water. The Byzantines' great defensive chain effectively kept the Ottomans out of the Golden Horn. On April 20, after about two weeks of the siege, a flotilla of four Christian ships slipped into the Golden Horn, bringing additional troops and badly needed supplies to the city. Mehmed was so angry that he threatened to execute the Turkish admiral. Only the testimony of his subordinates saved the man's life.
Consequently, Mehmed came up with a unique solution to circumvent the nautical chain. Using his large number of troops, Ottoman engineers constructed a road of greased logs north of the Galata suburb. On April 22, a number of Turkish vessels (one eyewitness claims 70 ships) were portaged from the Bosphorus to the Golden Horn, using oxen and manual strength. This act panicked the defenders, as the Turks now could threaten the entire length of the city's fortifications. On the night of April 28, the Byzantines attempted to burn the Turkish fleet, sending a number of fireships. The ships were sunk before they could do major damage. As a result, Byzantine troops were pulled from the Theodosian Walls in order to defend the walls along the Golden Horn.

"Mehmed II at the Siege of Constantinople" by Fausto Zonaro (1908)
Mehmed supervising the portage of his fleet from the Bosphorus into the Golden Horn
Oil on canvas, currently at the Dolmabahçe Palace, Istanbul, Turkey

After a number of inconclusive frontal assaults, the Turks sought to break through the walls by constructing underground tunnels in an effort to mine them (this was a technique going back to the ancient Assyrians) from mid-May to 25 May. Many of the sappers were miners of German origin sent by the Serbian ruler. However, the Byzantines employed an engineer named Johannes Grant (who was said to be German but was probably Scottish), who had counter-mines dug, allowing Byzantine troops to enter the mines and kill the Turkish workers. The defenders intercepted the first Serbian tunnel on the night of May 16. Subsequent tunnels were detected on May 21, 23, and 25; each was destroyed with Greek fire and vigorous combat. On May 23, the Byzantines captured and tortured two Turkish officers, who revealed the location of all the Turkish tunnels, which were then destroyed.
On May 21, Sultan Mehmed sent a message to Emperor Constantine. He offered to lift the siege if they gave him the city. He promised he would allow the emperor and any other inhabitant to leave with their possessions. Moreover, he would recognize the Byzantine ruler as governor of southern Greece (still nominally Byzantine territory). Lastly, he guaranteed the safety of the population that would remain in the city. Constantine XI accepted  to pay higher tributes to the sultan and recognized the status of all the conquered castles and lands in the hands of the Turks as Ottoman possession. However, with regard to the city, he told the sultan that he and his soldiers had resolved to give their lives to defend the city.

Shortly after receiving this reply, Mehmed held a final council of war to plan the final assault on Constantinople. Essentially, the Turks would mount a massive assault on the city's walls, hoping that sheer numbers would overwhelm the defenders after 40+ days of bombardment, mining, and fighting. The preparations took several days.
On May 28, with little hope left for reinforcements, large-scale religious processions were held in the city. In the evening a last solemn ceremony was held in the Hagia Sophia – the huge cathedral in the city's center – in which Emperor Constantine XI and representatives of both the Latin and Greek churches partook, together with nobility from all the nations defending the city. The defenders on the Theodosian Walls watched the preparations in silence. As if to dampen their ardor even further, as sundown approached the skies became heavily clouded, and rain began as it turned dark.
The Final Assault
Between midnight and 1:00 am in the wee hours of May 29, the final assault began. Driven forward by drums, horns, and fifies, the Christian troops of the Ottoman Empire attacked first, followed by the successive waves of the irregular Bashi-bazouks, and the regular Anatolians who focused on a section of the Blachernae walls in the northwest part of the city, which had been damaged by the cannon. This section of the walls had been built earlier, in the eleventh century, and was much weaker. The Anatolians managed to breach this section of walls and entered the city but were just as quickly pushed back by the defenders. Finally, as the battle was continuing, the last wave, consisting of elite Janissaries, attacked the city walls.

Final assault on Constantinople, May 29, 1453, artist unknown
Image is part of painting in the Panorama 1453 Museum, Istanbul, Turkey
[Image courtesy of http://rub-a-dub.blogspot.com]

Nearly every able-bodied man in Constantinople was on the walls, as were many women and even nuns. To add to the horrific din of the Ottoman cannonade and drums, every bell in every church in the city began to toll, until an unearthly din engulfed the scene. Giovanni Giustiniani, the Genoese general in charge of the land troops, was grievously wounded during the attack, and his removal from the ramparts caused a panic in the ranks of the defenders. [Giustiniani was evacuated by ship back to Chios, where he succumbed to his wounds a few days later.]
With Giustiniani's Genoese troops retreating into the city and towards the harbor, Constantine and his men, now left to their own devices, kept fighting and managed to hold off the Janissaries for a while, but eventually they could not stop them from entering the city. The defenders were also being overwhelmed at several points in Constantine's section. When Turkish flags were seen flying above a small postern gate, the Kerkoporta, which was left open, panic ensued, and the defense collapsed, as Janissary soldiers pressed forward. It is said that Constantine, throwing aside his purple regalia, led the final charge against the incoming Ottomans, dying in the ensuing battle in the streets like his soldiers. On the other hand, a Venetian eyewitness to the siege wrote in his diary that it was said that Constantine hanged himself at the moment when the Turks broke in at the San Romano gate, although his ultimate fate remains a mystery.

"Constantine Palaiologos [XI]" by Theophilus Hatzimihail (1932)
A fanciful portrayal of the last moments of the Byzantine emperor (on white horse at right)
Currently located in Theofilos Museum of Anakasia, Magnesia, Greece

After the initial assault, the Ottoman attackers fanned out along the main thoroughfare of the city, the Mese, past the great forums, many churches, and public buildings. The Turks converged upon the vast square that fronted the great church of Hagia Sophia whose bronze gates were barred by a huge throng of civilians inside the building, hoping for divine protection. After the doors were breached, the troops separated the congregation according to what price they might bring in the slave markets. They also began looting the church. With this final act, the siege of Constantinople was ended.
Aftermath
An estimated 4000 defenders of the city were killed, with a number surrendering and eventually being executed. As the city was being pillaged, some of the defenders escaped by boat, most of them making their ways to Venice and other Italian cities.
Ottoman casualties are unknown but they are believed by most historians to be very heavy due to several unsuccessful Ottoman attacks made during the siege and final assault. An Italian eyewitness described blood flowing in the city "like rainwater in the gutters after a sudden storm," and bodies of the Turks and Christians floating in the sea "like melons along a canal." [Mehmed had demonstrated that he was unconcerned with the number of casualties of his forces; he simply wanted to take Constantinople at any cost.]
Footnote #1: Mehmed allowed his troops to plunder the city for three days as it was customary. Soldiers fought over the possession of some of the booty. According to an eyewitness, "all through the day the Turks made a great slaughter of Christians through the city." Thousands of civilians were killed and an estimated 30,000 were enslaved or deported.
Footnote #2: Sultan Mehmed II finally entered the city after three days. When he saw the results of the looting done by his soldiers, he ordered guards put on many churches and other public buildings. For his final conquest of Constantinople, Mehmed was given the nom de guerre of Fatih (conqueror).

"Sultan Mehmed II The Conqueror"
Oil on wood panel, by a follower of Gentile Bellini (c. 1510)
Currently in National Portrait Gallery, London, UK

Footnote #3: In his first flush of victory, Mehmed gave amnesty to many of the nobles and bureaucrats of the city. However, after several days he experienced a change of heart and ordered the execution of many of these same men.
Footnote #4: The Hagia Sophia, one of the great landmarks of the Byzantine Empire, was converted into a mosque after Constantinople's fall. Since 1931, it has functioned as a museum. Between 1997 and 2006, a number of restoration projects have restored much of the building's former glory. [The current Hagia Sophia is the third church of the same name to reside on the site.]

Hagia Sophia Museum today, Istanbul, Turkey

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