Umayyad forces took Cyzicus (on the Sea of Marmara) and used it as a forward base, enabling sustained operations close to Constantinople during the first major Umayyad push against the Byzantine capital.
Umayyad land and naval forces began a major, multi-year effort to blockade and capture Constantinople, marking the first large-scale Umayyad attempt to deliver a decisive blow against Byzantium’s capital.
The Umayyad siege failed; Byzantine defenses (including naval operations) held, and the Umayyads ultimately withdrew, ending this phase of the campaign against the capital.
At Sebastopolis, an Umayyad army defeated Byzantine forces, effectively ending the period of relative peace and helping re-open sustained conflict on the frontier.
An Umayyad victory at Carthage concluded a major Byzantine attempt to contest North Africa, accelerating the collapse of Byzantine power in the Maghreb and altering the broader strategic balance between the empires.
Umayyad forces under Maslama ibn ʿAbd al-Malik (with al-ʿAbbas ibn al-Walid) besieged and took Tyana after a hard campaign. The siege’s exact year is disputed in the sources, but it is generally placed in 707–709.
After years of preparations, Maslama ibn ʿAbd al-Malik led a major invasion into Byzantine Asia Minor (716), setting conditions for the second and most dangerous Umayyad siege of Constantinople.
Umayyad forces initiated a combined land-and-sea siege of Constantinople (mid-717), attempting to starve and storm the city. Byzantine defenses, including naval resistance and alliances, played a decisive role.
After about a year, the Umayyads abandoned the siege (718). The failure was a major strategic setback, blunting Umayyad capacity for decisive conquest in Anatolia even as raids continued.
An Umayyad army penetrated deep into northwestern Anatolia and besieged Nicaea (July–August 727). The city held, and the Umayyads withdrew, marking the high-water point of deep post-718 penetrations toward the Bosporus.
A catastrophic Umayyad defeat by the Khazars at Marj Ardabil (December 730) forced the caliphate to divert men and attention to the Caucasus front, affecting the scale and effectiveness of operations on other fronts, including against Byzantium.
At Akroinon (740), Byzantine forces under Leo III and Constantine V defeated a major Umayyad expedition. The battle is often treated as a turning point that helped reduce the intensity of large-scale Umayyad incursions into Anatolia as the caliphate entered deeper crisis.
Umayyad Military Campaigns against Byzantium (c. 670–740)
