Siege of Constantinople
717 CE.
Shown on the map at 41.013°, 28.975°.
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. After wintering in the western coastlands of Asia Minor, the Arab army crossed into Thrace in the early summer of 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 partly neutralized soon after its arrival by the Byzantine navy through the use of Greek fire.
Text from the Wikipedia article Siege of Constantinople (717–718), licensed CC BY-SA 4.0.