The Siege of Constantinople in 717 AD: Defending Christian Civilization

Table of Contents

  1. Introduction
  2. The Byzantine Empire’s Turbulent Times
  3. The Rise of the Umayad Caliphate
  4. Preparations for the Siege of Constantinople
  5. Emperor Leo III’s Ascension
  6. The Siege of Constantinople
  7. The Harsh Winter and Bulgarian Intervention
  8. The Arab Retreat and Final Victory
  9. Conclusion


In the year 717 AD, Prince Maslama Ibn Abd Al Malik of the Umayad Caliphate stood before the imposing walls of Constantinople, contemplating the fate of Southern Europe and Christian civilization. This marked a pivotal moment in history, where the destiny of two great powers hung in the balance.

The Byzantine Empire’s Turbulent Times

The Byzantine Empire, in the years leading up to 717 AD, was embroiled in internal strife, witnessing the rise and fall of three emperors in quick succession. Sectarian conflicts plagued its people, while external threats loomed. To the north, the Bulgarian Empire posed a formidable challenge, while Arab raids in Anatolia kept the Byzantines on constant alert.

The Rise of the Umayad Caliphate

To understand this critical juncture in history, we must rewind 80 years to the reign of Emperor Heraclius. His reign was marked by devastating wars against the Sassanid Empire to the east. After years of conflict, a peace treaty was signed, but both empires were left exhausted. Meanwhile, in Arabia, a new force was emerging – the Muslim invasion.

Preparations for the Siege of Constantinople

Under the leadership of the Umayad Caliphs, the Arab tribes united and embarked on a mission to spread Islam. The Byzantine Empire, weakened by previous wars, could not withstand the onslaught. Provinces like Syria, Palestine, Egypt, and Anatolia fell to the Arab forces. The Byzantine Empire lost its most vital territories and its primary sources of revenue.

Emperor Leo III’s Ascension

In 715 AD, Prince Maslama set his sights on the ultimate prize, Constantinople. Emperor Anastasius II, fearing war, began preparations to defend the city. The walls of Constantinople were fortified, and supplies were stockpiled. The city’s garrison was bolstered, and a formidable navy equipped with Greek fire, a deadly weapon, was readied.

The Siege of Constantinople

As Prince Maslama advanced on Constantinople in 717, he faced the imposing walls of Theodosius, a city that was no easy conquest. Arab forces surrounded the city, but the Byzantine navy, armed with the devastating Greek fire, disrupted their plans. The Arabs settled in for a blockade.

The Harsh Winter and Bulgarian Intervention

Winter set in, and the harsh conditions took a toll on the Arab forces. Hunger and disease spread, and their weaponry deteriorated. Meanwhile, the Bulgarian ruler, Khan Tervel, honored a treaty with the Byzantines and harassed the Arab rear. Reinforcements sent by the Caliph suffered defeat.

The Arab Retreat and Final Victory

As Arab morale dwindled and their fleet suffered losses, Prince Maslama was recalled. During the retreat, the Bulgars dealt a crippling blow to the Arab forces, further sealing their fate. The Byzantine Empire emerged victorious, and Constantinople remained unconquered by Arab forces.


The successful defense of Constantinople in 717 AD was a turning point in history. It safeguarded the Byzantine Empire and prevented the Arab conquest of Southern Europe. The Umayad Caliphate, although formidable, would later face internal strife and be overthrown by the Abbasids. This pivotal moment demonstrated the resilience and strategic brilliance of the Byzantines in the face of adversity.

  1. How did the Byzantines successfully defend Constantinople during the siege?

    The successful defense of Constantinople in 717 AD can be attributed to several factors. Emperor Leo III took swift action upon ascending to the throne, fortifying the city’s walls, amassing supplies, and bolstering the garrison. The Byzantine navy, equipped with the formidable Greek fire, disrupted Arab naval operations. The harsh winter and the intervention of the Bulgarian ruler Khan Tervel further weakened the Arab forces. Ultimately, the combined efforts of the Byzantine defense and strategic setbacks for the Arabs led to the preservation of Constantinople.

  2. Why did Prince Maslama Ibn Abd Al Malik target Constantinople in 717 AD?

    Prince Maslama Ibn Abd Al Malik, representing the Umayad Caliphate, aimed to conquer Constantinople in 717 AD due to the city’s strategic significance and the prophecy that the conqueror of Constantinople would bear the name of a prophet. Additionally, the weakened state of the Byzantine Empire, with internal strife and external threats, presented what seemed to be a favorable opportunity for the Arab forces.