Siege of Constantinople: The Ultimate Clash

Siege of Constantinople: A Culmination of Years of Conflict

The Siege of Constantinople, which took place between 717 and 718, was a pivotal moment in the conflict between the Muslim Arabs of the Umayyad Caliphate and the Byzantine Empire. The siege was the culmination of twenty years of attacks and progressive Arab occupation of the Byzantine borderlands, while Byzantine strength was sapped by prolonged internal turmoil.

The Arabs’ Plans and Their Alliance with General Leo III

In 716, after years of preparations, the Arabs, led by Maslama ibn Abd al-Malik, invaded Byzantine Asia Minor. The Arabs initially hoped to exploit Byzantine civil strife and made a common cause with the general Leo III the Isaurian, who had risen up against Emperor Theodosius III. Leo, however, tricked them and secured the Byzantine throne for himself.

The Siege and the Byzantine Defense

After wintering in the western coastlands of Asia Minor, the Arab army crossed into Thrace in the early summer 717 and built siege lines to blockade the city, which was protected by the massive Theodosian Walls. The Arab fleet, which accompanied the land army and was meant to complete the city’s blockade by sea, was neutralized soon after its arrival by the Byzantine navy through the use of Greek fire. This allowed Constantinople to be resupplied by sea, while the Arab army was crippled by famine and disease during the unusually hard winter that followed.

The Arab Defeat and Its Consequences

In the spring of 718, two Arab fleets sent as reinforcements were destroyed by the Byzantines after their Christian crews defected, and an additional army sent overland through Asia Minor was ambushed and defeated. Coupled with attacks by the Bulgars on their rear, the Arabs were forced to lift the siege on 15 August 718. On its return journey, the Arab fleet was almost completely destroyed by natural disasters.

The significance of the Siege

The siege’s failure had wide-ranging repercussions. The rescue of Constantinople ensured the continued survival of Byzantium, while the Caliphate’s strategic outlook was altered: although regular attacks on Byzantine territories continued, the goal of outright conquest was abandoned. Historians consider the siege to be one of history’s most important battles, as its failure postponed the Muslim advance into Southeastern Europe for centuries.

Byzantium: The Surprising Life of a Medieval Empire
Byzantium: The Surprising Life of a Medieval Empire by Judith Herrin
History of the Byzantine Empire by George Finlay
History of the Byzantine Empire by George Finlay

Arab Sieges and Byzantine Ascendancy

Miniature 47 from the Constantine Manasses Chronicle, 14 century: The arabs attacking Constantinople during the reign of emperor Leo III

Miniature 47 from the Constantine Manasses Chronicle, 14 century: The arabs attacking Constantinople during the reign of emperor Leo III

After the initial Arab siege of Constantinople from 674 to 678, a period of relative peace ensued between the Arabs and Byzantines. However, following the Second Muslim Civil War in 680, the Umayyad Caliphate was weakened, and the Byzantine Empire took advantage of this by extracting immense amounts of tribute from the Umayyad government in Damascus. This period of Byzantine ascendancy did not last long as the Umayyads emerged victorious from their civil war, and in 692, Emperor Justinian II resumed hostilities with the Caliphate.

The Arab Victories and the Collapse of the Byzantine Defensive System

The result was a series of Arab victories that led to the gradual encroachment upon Byzantine borderlands, the loss of Byzantine control over Armenia and the Caucasian principalities, and the capture of fortresses and towns. As time passed, the Arab raids penetrated further and further into Asia Minor, border fortresses were repeatedly attacked and sacked, and references to Byzantine reaction in the sources become scarce. After 712, the Byzantine defensive system began to show signs of collapse, leaving the empire vulnerable to Arab attacks.

The Internal Instability of the Byzantine Empire and the Threat to its Capital

The Arabs were further aided in their efforts to capture the Byzantine Empire by the prolonged period of internal instability that followed the first deposition of Justinian II in 695. The Byzantine throne changed hands seven times in violent coups, weakening the empire from within. The Arab attacks intensified after the end of their own civil war, and with far more men, land, and wealth than Byzantium, the Arabs began to concentrate all their strength against it. The Arabs posed a significant threat to the Byzantine Empire by attempting to capture its capital, and there was a possibility that they would extinguish the empire entirely.

Byzantine and Arab Sources

Theophilus of Edessa’s Detailed Account

The Siege of Constantinople in 717-718 CE has been recorded in various sources, but the information available today is often contradictory. The primary Byzantine sources include the Chronicle of Theophanes the Confessor (760-817 CE) and the Breviarium of Patriarch Nikephoros I of Constantinople (d. 828 CE), which differ only slightly in terms of chronological details.

Theophanes and Nikephoros both relied on a primary account written during the reign of Leo III the Isaurian (r. 717-741 CE), which portrayed him in a favorable light. Theophanes also used an unknown biography of Leo for the events of 716 CE, while Nikephoros did not. The 8th-century chronicler Theophilus of Edessa provided a detailed account of the years leading up to the siege and the siege itself, with a focus on the diplomatic exchanges between Maslama and Leo III.

Arab Sources: Kitab al-‘Uyun and History of the Prophets and Kings

On the other hand, the Arab sources, including the Kitab al-‘Uyun (11th century CE) and the History of the Prophets and Kings by al-Tabari (838-923 CE), relied on primary accounts by early 9th-century Arab writers but were more confused and contained several legendary elements. The Syriac language accounts, based on Agapius of Hierapolis (d. 942 CE), were brief and likely drew from the same primary source as Theophanes.


Preparations, Troop Numbers, and Composition of Forces

Arab Preparations for Assault on Constantinople

From the very beginning, it was clear that the Arabs were preparing for a major attack on Constantinople. The Syriac Zuqnin Chronicle, dating back to the late 8th century, reported that the Arab forces were “innumerable.” However, this was a conservative estimate when compared to the 12th-century Syriac chronicler Michael the Syrian, who claimed that the Arab army comprised 200,000 men and 5,000 ships. Other sources report varying numbers, with al-Mas’udi, a 10th-century Arab writer, suggesting 120,000 troops and Theophanes the Confessor mentioning 1,800 ships. The Arab forces had hoarded supplies for several years and had stockpiled siege engines and incendiary materials like naphtha.

The Supply Train and Troop Numbers

According to historical accounts, the supply train alone was said to have included 12,000 men, 6,000 camels, and 6,000 donkeys. Furthermore, the troops included 30,000 volunteers for the Holy War or Jihad, as reported by the 13th-century historian Bar Hebraeus. On the other hand, the number of defenders of Constantinople remains uncertain, although it is likely that they did not exceed 15,000 men. Given the Byzantine Empire’s manpower limitations and the need to feed and maintain a force, it is reasonable to assume that their strength was not substantial.

Composition of the Arab Force

While the composition of the Arab force is not entirely clear, it is believed that it mainly consisted of Syrians and Jazirans of the elite ahl al-Sham or “People of Syria.” These individuals were veterans of the struggle against Byzantium and the mainstay of the Umayyad regime. Maslama, the commander-in-chief of the Arab forces, led the attack and was joined by lieutenants such as Umar ibn Hubayra, Sulayman ibn Mu’ad, and Bakhtari ibn al-Hasan. According to Agapius of Hierapolis and Theophanes, who provided accounts of the attack, these were the most prominent lieutenants of Maslama. Later sources replace Bakhtari with Abdallah al-Battal.

The Siege’s Duration and its Impact

Despite consuming a significant portion of the Caliphate’s resources and manpower, the Arab forces still had the capacity to launch raids on the Byzantine frontier in eastern Asia Minor during the siege’s duration. In 717, Caliph Sulayman’s son Daud captured a fortress near Melitene, and in 718, Amr ibn Qais raided the frontier. On the Byzantine side, the numbers are unknown, but it is clear that they could count on the support of the Bulgar ruler Tervel. Leo had negotiated a treaty with him that might have included an alliance against the Arabs.


Maslama's Siege of Constantinople

Restored section of the Walls of Constantinople.

Restored section of the Walls of Constantinople.

In the early summer of the year, Maslama gave orders to his fleet to join him as he led his army across the Hellespont at Abydos into Thrace. The Arab forces wasted no time in thoroughly devastating the countryside, gathering supplies, and sacking the towns they encountered as they marched towards Constantinople. They arrived in mid-July or mid-August and began isolating the city completely on land by constructing a double siege wall of stone, with their camp positioned between them.

Refusal to Ransom Constantinople

According to Arab sources, at this point, Leo offered to ransom the city by paying a gold coin for every inhabitant. However, Maslama rejected the offer, stating that there could be no peace with the vanquished and that the Arab garrison of Constantinople had already been selected.

The Arrival of Sulayman’s Fleet

The Arab fleet under Sulayman arrived on 1 September, anchoring near the Hebdomon before leading their various squadrons into the Bosphorus. One part of the fleet sailed south of Chalcedon to watch over the southern entrance of the Bosporus, while the rest sailed into the strait, passing by Constantinople and making landfall on the coasts between Galata and Kleidion, cutting the Byzantine capital’s communication with the Black Sea.

The Byzantine Victory

As the Arab fleet’s rearguard was passing the city, the southerly wind stopped and then reversed, causing them to drift towards the city walls. A Byzantine squadron attacked them with Greek fire, causing some of the ships to sink with all hands while others burned and sailed down to the Princes’ Islands of Oxeia and Plateia. This victory encouraged the Byzantines and dejected the Arabs, who had originally intended to sail to the sea walls during the night and try to scale them using the ships’ steering paddles. That same night, Leo drew up the chain between the city and Galata, closing the entrance to the Golden Horn. The Arab fleet became reluctant to engage the Byzantines and withdrew to the safe harbor of Sosthenion further north on the European shore of the Bosporus.

The Arab Army’s Strategic Supplies and Limited Foraging

Amidst the backdrop of the siege of Constantinople, the Arab army was well-provisioned with an abundance of supplies that were piled high in their camp. The Arab accounts reported that they had even brought along wheat to sow and harvest the following year. However, the Byzantines were not to be outdone. The failure of the Arab navy to blockade the city meant that the Byzantines too could ferry in provisions. Although the Arab army had already devastated the Thracian countryside during its march, they could not rely on it for foraging. The Arab fleet and the second Arab army operating in the Asian suburbs of Constantinople were only able to bring in limited supplies to Maslama’s army.

Negotiations and Double Dealing

As the siege progressed and the winter months approached, negotiations opened between the two sides. These negotiations were extensively reported by Arab sources but ignored by Byzantine historians. According to the Arab accounts, Leo continued to play a double game with the Arabs. One version claims that he tricked Maslama into handing over most of his grain supplies, while another claims that the Arab general was persuaded to burn them altogether, so as to show the inhabitants of the city that they faced an imminent assault and induce them to surrender.

The Terrible Winter and Famine

The winter of 718 was especially harsh with snow covering the ground for over three months. As the supplies in the Arab camp ran out, a terrible famine broke out. The soldiers were forced to eat their horses, camels, and other livestock, as well as the bark, leaves, and roots of trees. They even swept the snow off the fields they had sown to eat the green shoots, and reportedly resorted to cannibalism and eating the dung of each other and their animals. Consequently, the Arab army was ravaged by epidemics, and with great exaggeration, the Lombard historian Paul the Deacon put the number of their dead of hunger and disease at 300,000.

Arab Reinforcements Arrive, But Betrayal and Fire Destroy Them

In the spring of the year, hope was kindled in the hearts of the Arabs when the new Caliph, Umar II, dispatched two fleets and a fresh army to aid those besieging Constantinople. The 400 ships from Egypt, led by Commander Sufyan, and the 360 ships from Africa, under the command of Izid, were loaded with supplies and arms. The fleets arrived in the Sea of Marmara, anchoring on the Asian shore. The Egyptians anchored in the Gulf of Nicomedia while the Africans anchored south of Chalcedon.

However, despite the new reinforcements, most of the Arab fleets’ crews were Christian Egyptians who began deserting to the Byzantines upon their arrival. Leo, the Byzantine Emperor, launched an attack against the Arab fleets after being notified by the Egyptians of their arrival and disposition. Crippled by the defection of their crews and unable to withstand the Greek fire, the Arab ships were destroyed or captured along with the weapons and supplies they carried. The city of Constantinople was now safe from a seaborne attack.

Byzantine Victories on Land and Sea

The Byzantines continued their successful campaign, ambushing the advancing Arab army under Commander Mardasan and destroying it in the hills around Sophon, south of Nicomedia. Constantinople was easily resupplied by sea, and the city’s fishermen resumed their work. However, the Arabs still suffered from hunger and pestilence and lost a major battle against the Bulgars, who killed 22,000 men.

The End of the Siege and Arab Defeat

After thirteen months of siege, the Arabs retreated from Constantinople on August 15, 718. The date coincided with the feast of the Dormition of the Theotokos, which the Byzantines attributed their victory. The Arab fleet, which was not hindered on its retreat, lost more ships in a storm in the Sea of Marmara, while other ships were set on fire by ashes from the volcano of Santorini. Some of the survivors were captured by the Byzantines, and only five vessels made it back to Syria.

According to Arab sources, 150,000 Muslims perished during the campaign, a number that, while certainly inflated, is indicative of the enormity of the disaster.


Related Features

The Umayyad Caliphate Invasion of Spain

The Umayyad Caliphate Invasion of Spain

The Umayyad Caliphate expanded into Hispania from 711 to 718. The conquest resulted in the defeat of the Visigothic Kingdom and the establishment of Al-Andalus.

8th Century: A Time of Transformation

8th Century: A Time of Transformation

The 8th century: a time of transformative change that shaped the world, from the rise of Islam to the Viking Age.

Legacy of the Viking Age: Shaping Europe

Legacy of the Viking Age: Shaping Europe

Legacy of the Viking Age: A profound impact on European history seen in names, traditions, and cultural heritage of Northern Europe.

Featured Image

Siege of Constantinople - Image from an illuminated manuscript, the Madrid Skylitzes, showing Greek fire in use against the fleet of the rebel

Image from an illuminated manuscript, the Madrid Skylitzes, showing Greek fire in use against the fleet of the rebel en:Thomas the Slav

The miniature 47 from the Constantine Manasses Chronicle is a vivid depiction of the Arab siege of Constantinople during the reign of Emperor Leo III in the 8th century. The intricate details in the artwork, from the soldiers’ armor to the ships’ sails, speak to the skill of the 14th-century artist who created it. The scene shows the Arab soldiers and their ships surrounding the city walls, while the Byzantine defenders fire arrows at them. The chaos and brutality of the siege are captured in the flames of burning ships and the soldiers falling from the walls.

This miniature is not only a piece of art but also serves as a testament to the importance of art in chronicling historical events and preserving them for future generations. It provides a visual representation of the conflict, bringing history to life and providing a unique insight into the past. The miniature also reminds us of the significance of Constantinople as a pivotal city in history and the role it played in shaping the world we live in today.

Miniature 47 is part of the Constantine Manasses Chronicle, a medieval Byzantine chronicle written in Greek during the 12th century. The manuscript consists of a compilation of historical events and figures from ancient times to the late 12th century. It is believed that the manuscript was created during the reign of Manuel I Komnenos, who ruled from 1143 to 1180.

The miniatures within the manuscript were added during the 14th century and are considered to be some of the finest examples of Byzantine art. The artist responsible for the miniatures is unknown, but their work is highly regarded for its intricate detail and vivid depiction of historical events.

Miniature 47 specifically depicts the Arab siege of Constantinople during the reign of Emperor Leo III in the 8th century. It is a testament to the importance of art in preserving historical events and is a valuable resource for historians studying Byzantine history.



  • Norwich, J. J. (1997). A Short History of Byzantium. Vintage Books.

  • Kaegi, W. E. (2008). Byzantine Military Unrest, 471-843: An Interpretation. Routledge.

  • Kaldellis, A. (2015). The Byzantine Republic: People and Power in New Rome. Harvard University Press.

  • Wikipedia Contributors. (2023, February 10). Siege of Constantinople (717–718). Wikipedia; Wikimedia Foundation.
  • Siege of Constantinople (717–718). (2023). DBpedia.

License & Copyright

The copyright holder has published this content under the following license: Creative Commons Attribution-NonCommercial-ShareAlike. This license lets others remix, tweak, and build upon this content non-commercially, as long as they credit the author and license their new creations under the identical terms. When republishing on the web a hyperlink back to the original content source URL must be included. Please note that content linked from this page may have different licensing terms.

If I have mistakenly misused any of your content, artwork, images or videos, please contact me on and I will take the necessary corrective action.


    Home » History » Battles » Siege of Constantinople: The Ultimate Clash
    Help Preserve Medieval History!
    Would love your thoughts, please comment.x
    Verified by MonsterInsights