Amid the upheaval in the Islamic world following Muhammad’s death, the Umayyad Caliphate lasted for less than a century, but it spent that time becoming one of the most influential of the major caliphates. Its official existence was from 661-750, and the rulers were the male members of the Umayyad dynasty, roughly translated from Arabic as the “Sons of Umayyah.” Its primary base of power was in Syria following the creation of a dynastic, hereditary rule headed by one of Syria’s long-lasting governors, Muawiya ibn Abi Sufyan.

The Umayyads also constantly fought the Byzantines, and on August 15, 717, their formidable army, under the command of General Maslama ibn 'Abd al-Malik, arrived in Thrace and laid siege to the imposing walls of Constantinople. This event, which lasted a full year until August 15, 718, represented the apex of the Islamic expansionist project aimed at definitively eradicating the Byzantine Empire and subjugating its seemingly impregnable capital.

The siege of 717–718 was of great significance, marking a crucial and irreversible turning point in the history of Europe and the Middle East. Renowned scholars such as Henri Pirenne and Edward Gibbon have noted that the survival of Western Civilization itself hung in the balance beneath the walls of Constantinople, because an Arab victory would have opened the gates of Eastern Europe and the Balkans to Islam, rendering the Rhine as vulnerable as the Euphrates and altering the political and religious equilibrium of the European continent forever. The failure of this enormous undertaking therefore represented the most significant setback ever experienced by Islamic armies, reinforcing Byzantium's role as an impregnable guardian of Christendom for centuries to come.