Climbing the Walls: 8 Failed Sieges of Constantinople

2 – Sassanid Persians & Avars (626)

The siege of 626 is better documented than the events of 559 and it involved a huge force of 80,000 men, comprised of Avars, Slavs, and Persians. The war between the Byzantines and Sassanids had dragged on since 602 with no clear advantage to either side although both empires were massively weakened by the fighting. By the seventh century, the Avars, a group of Eurasian nomads, were another threat to the Empire. They were defeated by the Byzantines in 619 but returned seven years later on a mission to destroy their enemies.

The city of Constantinople was ripe for conquest in 626 as Emperor Heraclius was away in eastern Anatolia in a campaign against the Persians. There was a riot in the city in May because one of Constantinople’s leaders wanted to cut bread rations and also increase the price of bread. The Persian leader, Khosrau, sensed an opportunity and recruited two armies in a bid to end the war once and for all.

Khosrau coordinated the attack with the leader of the Avars; the Persians would attack from the east, and the Avars would hit the city from the west. Since the Byzantine navy controlled the Bosporus Strait, the Persians could not send reinforcements to the Avars. This proved crucial because while the Persians were siege warfare experts, the Avars were not.

The assault began on June 29 as 12,000 expertly trained Byzantine troops guarded the city. Led by Bonus and Sergius, the defenders held off the enemy for over a month. Morale remained high as the inhabitants believed that they were under divine protection. After multiple failed assaults, the raiders were forced to flee when the Persian and Avaric fleets were sunk in different fights. The siege was effectively over on August 7, and three days later, the Avars burned their siege engines and withdrew.

3 – The Umayyad Caliphate I (674 – 678)

This was the first of two major sieges by the Umayyad Caliphate and lasted a total of four years. In 661, Caliph Mu’awiya I emerged as the leader of the Muslim Arab Empire after winning a civil war. The catastrophic defeat at Yarmouk in 636 had forced the Byzantines to withdraw most of their remaining army to Asia Minor. By leaving the Levant, they opened up a path for the Rashidun Caliphate to conquer Syria and Egypt. Further inroads were made until the First Muslim Civil War which resulted in a temporary halt in attacks.

However, Mu’awiya resumed the attacks on the Byzantines and ravaged Asia Minor annually from 663 onwards. Each year, they returned to their Syrian bases. After several years, Mu’awiya knew it was necessary to capture Constantinople if the Arabs wished to secure Asia Minor. Over the next few years, the Arabs implemented a methodical approach and took important locations such as Kyzikos and Smyrna in 670. By 672/73, the Arabs fleets took several bases around the Asia Minor coast and began a loose blockade on the city of Constantinople.

The Arabs launched attacks on the city’s fortifications every spring for four years and retreated to Cyzicus in winter. Although the Arabs were not having an enormous amount of success, Emperor Constantine IV knew he needed to lift the siege to save other parts of the Empire. At that time, the Lombards attacked territory in Italy while the Slavs attacked Thessalonica. Constantine took a risk and decided to fight the Arabs in a head-on battle in 678.

Eventually, Byzantine ships sailed out of the Golden Horn and attacked the enemy with a secret weapon known as Greek Fire. The exact make-up of the weapon is still not known today. It was shot via a siphon and ignited a flame that enemies were unable to extinguish. At the same time, a Byzantine land army defeated a Muslim army in Asia Minor. The enormous losses suffered by the Arabs forced them to retreat, but they would be back within 40 years.

4 – The Umayyad Caliphate II (717 – 718)

After the failed siege, the Arabs retreated and what followed was a period of peace. Aside from having to recover after sustaining a huge number of losses, the Umayyad Caliphate found itself in the midst of the Second Muslim War. It was only after 692, when the Umayyad settled the issue, that hostilities between the Arabs and Byzantines resumed.

The beginning of the eighth century was a grim time for the Byzantine Empire as the Arabs started to make inroads. By 712, the Byzantine defenses appeared primed for a collapse, so the Arabs raided deeper and deeper into Asia Minor where they attacked and sacked enemy fortresses on the border. At that stage, the Arabs were taking full advantage of instability within the Byzantine Empire as the throne changed hands on multiple occasions within a few years of the deposition of Justinian II.

Eventually, the Arabs were ready for a full-scale assault on Constantinople which began in 717. They had at least 120,000 men and 1,800 ships while the Arab supply train featured 12,000 men, 6,000 camels, and 6,000 donkeys. Historians don’t know how many people defended the Byzantine capital, but they were significantly outnumbered by the Arabs. The Arabs devastated the countryside surrounding the city and began the siege in July or August. Arab sources claim that Emperor Leo III offered to pay one gold coin for every inhabitant of the city in a bid to get the invaders to leave.

The city appeared doomed as the determined besiegers had ample supplies but as the Arab navy failed to blockade the city, the Byzantines were able to hold firm. In hindsight, destroying the land near the city was a bad idea because when winter came, the Arabs suddenly found themselves struggling for provisions. The winter of 717/718 was particularly harsh and led to a famine amongst the besiegers. Disease ravaged the invaders, and they suffered tens of thousands of casualties.

In the spring of 718, two new Arab fleets arrived but promptly defected to the Byzantines as most of the crew were comprised of Christian Egyptians. Leo ordered an attack as soon as he heard the news and the Arab ships were destroyed; once again, the Byzantines used Greek Fire to great effect. With the city safe from a sea attack, a land army met the Muslims near Nicomedia and annihilated an Arab army. Up to 150,000 Arabs died in the failed attempt to take Constantinople.

5 – The Bulgarians (813)

Khan Krum is one of the best-known leaders of Bulgaria as he managed to double the kingdom’s territory during his 11+ year reign. Krum’s desire to expand Bulgarian territory led to direct conflict with the Byzantines. He enjoyed several notable victories over his new enemy including a win at Struma valley in 807 and two years later when he forced a garrison at Serdica to surrender. He gained notoriety for slaughtering the 6,000 men at Serdica despite making a promise to spare their lives if they surrendered.

Krum won his most famous victory at the Battle of Pliska in 811 when the Byzantine Emperor, Nikephoros I, was killed in battle. He continued marching forward and had another major victory at the Battle of Versinikia in 813 when he routed the army of Emperor Michael I Rangabe. Michael was forced to abdicate in favor of Leo V (the Armenian). By now, the city of Constantinople was in Krum’s sights, and he reached the outskirts just six days after Leo was crowned.

However, his attempt to intimidate the city into surrender failed, and he decided to ravage the surrounding land for a few days. After a meeting where the Byzantines tricked the Bulgarians, the irate Krum sought vengeance, and he started pillaging and destroying as many monuments and ornaments near the city as possible. Krum spent the winter of 813 preparing for a new attack.

Meanwhile, Leo ordered the creation of a new wall outside of the one built during the reign of Heraclius and a wide moat was dug. However, the precautions were unnecessary because, on April 13, 814, Khan Krum died before he could launch his latest assault. He was succeeded by his son, Omurtag, but the ensuing struggle for succession ensured the end of the Bulgarian attempts to take Constantinople. One wonders whether or not Krum would have been the first to take the city had he not died.

6 – The Rus’ Trilogy (860, 907 & 941)

The Rus’ were Norsemen who made their way to northeastern Europe and gave their name to the lands of Belarus, Russia, and Ruthenia. They made three unsuccessful attempts to take the city of Constantinople in less than a century. The origin of the Rus’ dispute with the Byzantines seems to stem from the creation of the fortress Sarkel in the 830s. Byzantine engineers created it for the Khazars, and it restricted the Rus’ trade route along the Don River.

The Rus’ clearly had good intel because their attack in 860 was exceptionally well-timed. It came just as the Byzantines were struggling to repel the Abbasids in Asia Minor. On June 18, 860, approximately 200 Rus’ vessels sailed into the Bosporus and attacked the countryside surrounding Constantinople. The sudden attack caught the Byzantines off-guard and Emperor Michael III, and the navy (along with its Greek Fire) was absent. The invasion apparently lasted until August 4. Historians aren’t sure why the Rus retreated. Perhaps Michael returned and forced the invaders to retreat?

The second Rus’ attack on Constantinople occurred in 907 and, according to Oleg of Novgorod’s Primary Chronicle; it was part of the Rus’-Byzantine War that year. He claims that a Rus’ fleet of 2,000 ships, led by Oleg of Kiev, outsmarted the Byzantines and circumnavigated the iron chains which initially prevented his ships from reaching the gates of the city. The Primary Chronicle suggests that Oleg forced the Byzantines into peace negotiations and left with an enormous sum of money.

According to the Khazar Correspondence, Igor of Kiev led another Rus’ attack on Constantinople in 941. Along with the Pechenegs, the Rus’ reached Bithynia in May 941 and were informed that the Byzantine capital was vulnerable because the Empire’s fleet was fighting the Arabs on the Mediterranean while the land army was stationed on eastern borders. Emperor Romanus I Lecapenus could only muster 15 retired ships and fitted them with Greek Fire.

Unaware of the power of Greek Fire, Igor’s fleet surrounded the Byzantines. The ships were so close together than the fire ravaged the entire fleet of the Rus’ and their allies and some of the Rus’ jumped overboard and drowned while the captured Rus’ were beheaded. In September, two Byzantine generals returned to Constantinople with their armies while the navy also returned. A surprise attack led to the destruction or capture of most of the Rus’ fleet while captured Rus’ were executed. Igor escaped to the Caspian Sea but was killed while fighting the Arabs.

7 – Bulgarian & Nicaean Forces (1235)

After Constantinople was sacked during the Fourth Crusade in 1204, a new Empire, known as the Latin Empire, was formed by the leaders of the conquest. They set up their empire on lands acquired from the Byzantines and on May 16, 1204, Baldwin I was crowned as the first Emperor. The Latin Empire lasted less than 60 years as it failed to establish any sort of dominance. Also, the Latin’s only had a relatively small amount of territory; other states claimed to be the successor to the Eastern Roman Empire including the Empire of Nicaea.

However, the Latin Empire did include Constantinople, the capital of the Byzantine Empire, which was coveted by various entities. By the late 1220s, the Nicaea Empire emerged as the biggest threat to the Latin Empire as it began acquiring territories in Greece. The Nicaean Emperor, John III Doukas, forged an alliance with Bulgaria (and its leader Ivan Asen II) and in 1235, the combined might of the new allies attempted to take Constantinople.

The Latin Empire’s leader, Emperor John of Brienne, was trapped in the city but the second Duke of the Archipelago, Angelo Sanudo, intervened on behalf of Constantinople by sending a naval squadron to help John of Brienne. As a result, the Latin’s were able to hold off the invaders until the winter forced the Bulgar/Nicaean alliance to retreat. Despite initially agreeing to continue the siege in 1236, Asen refused to send troops. John of Brienne died in 1237, and the Bulgars broke the treaty with Nicaea because of the possibility of Asen becoming the Latin Empire’s regent.

However, the Nicaeans refused to quit and continued their plan to regain Constantinople. They had the city more or less surrounded by 1247, and a victory at the Battle of Pelagonia in 1259 was the beginning of the end of the Latin Empire. Although Michael VIII Palaiologos failed to take Constantinople in a siege in 1260, the Nicaeans finally landed their prize on July 25, 1261. Instead of embarking on yet another lengthy siege, a general named Alexios Strategopoulos found an unguarded entrance and claimed the city for Emperor Michael VIII.

8 – The Ottomans (1422)

By the beginning of the fifteenth century, the Byzantine ‘Empire’ was little more than a few strips of land and the city of Constantinople which repelled fierce attacks for decades before finally falling in 1453. The Ottomans made their first attempt at capturing the city in 1411, but the timing was wrong. The Ottoman Empire was in turmoil because of a Civil War that began in 1402 and didn’t end until 1413. Musa Celebi was unable to take the city because his brother, Mustafa (later Mehmed I) helped John VIII Palaiologos and his ‘retired’ father, Manuel II, defeat the invaders.

When Mehmed I died in 1421, he was succeeded by his son, Murad II. The Ottomans had cannon for the first time at this stage, and Murad was eager to test out his weaponry on Constantinople. According to a witness named John Kananos, Murad built a huge rampart from the Sea of Marmora to the Golden Horn. His troops sent volleys of fire and stones from catapults over the city’s walls.

A man named Sei-Bokhari, who claimed to be descended from Muhammad, foretold the fall of Constantinople on August 24. As a result, the Sultan planned his major assault for that day. After a long and difficult battle, the Turks began to panic and inexplicably burnt their encampments and retreated. Sources at the time believe that Emperor Manuel II sent word that he would help champion the cause of Mustafa, Murad’s main rival for the Sultanate. As a result, Murad had to abandon the siege to deal with the usurper and the unfortunate Mustafa was soon captured and strangled.

Constantinople was only breached a small number of times in its history of over 1,000 years as the capital of the Byzantine Empire. However, it was unable to hold out for much longer and on May 29, 1453, the Ottomans, under the rule of Mehmed the Conqueror, finally captured the city after a 53-day siege. The last Byzantine Emperor, Constantine XI, was killed in the fight but his body was never found.