Siege of Constantinople

Overview

In 717–718, Constantinople, the capital of the Byzantine Empire, was besieged by the Muslim Arabs of the Umayyad Caliphate. The campaign marked the culmination of twenty years of attacks and progressive Arab occupation of the Byzantine borderlands, while Byzantine strength was sapped by prolonged internal turmoil. 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 common cause with the general Leo III the Isaurian, who had risen up against Emperor Theodosius III. Leo, however, deceived them and secured the Byzantine throne for himself.

Overview adapted from Wikipedia, licensed under CC BY-SA 4.0.

Significance

The Umayyad siege of Constantinople in 717 was among the most ambitious military undertakings of the Arab–Byzantine wars, deploying a reported 120,000 troops against a Byzantine garrison of 15,000 in an attempt to take the city that served as the intersection of Europe and Asia along the Bosporus, connecting the Sea of Marmara and the Black Sea. Constantinople's position on the Silk Road gave it exceptional strategic value, and its capture would have represented a transformative blow to Byzantine power and a gateway for Umayyad expansion into Europe. The Umayyad Caliphate committed forces under Maslama ibn Abd al-Malik, with backing from the caliphs Sulayman ibn Abd al-Malik and later Umar ibn Abd al-Aziz, alongside commanders including Umar ibn Hubayra and Abdallah al-Battal. The Byzantine defense was organized under Leo III the Isaurian, with support from the Bulgarian ruler Tervel. The campaign ended at enormous cost to the Umayyad side, with recorded losses of 150,000, exceeding the entire initial force — a figure that points to catastrophic attrition over the course of the siege. The failure to take Constantinople preserved Byzantine control of the Bosporus corridor and checked Umayyad expansion westward, marking one of the most consequential repulses of the Arab–Byzantine conflict.

Forces & casualties

Commanders (7)