Leo III ("the Isaurian") entered Constantinople and replaced Theodosius III, marking the start of the Isaurian dynasty amid the empire’s late-7th/early-8th-century political instability.
Umayyad forces began a major land-and-sea siege of Constantinople, a critical test of the reconstituted Byzantine state under Leo III.
The siege was lifted after severe Umayyad losses and effective Byzantine defense (including naval operations), helping stabilize the empire’s eastern frontier for decades.
Leo III elevated his son Constantine V as co-emperor, strengthening dynastic succession during ongoing military pressure on the empire.
Leo III promulgated the Ecloga, a Greek-language selection and reform of Roman law intended to guide judges and administration, and influential in later Byzantine and Slavic legal traditions.
In the early phase of imperial iconoclasm, Leo III ordered removal of a prominent image of Christ from the Chalke Gate (replaced with a cross), a move that became emblematic of the emerging controversy over sacred images.
A court council in Constantinople (traditionally dated to 730) is associated with Leo III’s formal prohibition of depictions of religious figures, sharpening the state’s iconoclastic policy.
Leo III and Constantine V defeated a major Umayyad raid force at Akroinon. The victory was later treated (especially in Byzantine tradition) as validating imperial policy, including iconoclasm, though historians debate its broader strategic decisiveness.
After Leo III’s death, Constantine V faced a coup by Artabasdos, who ruled as rival emperor during a civil war that also intersected with religious politics around images.
Constantine V defeated Artabasdos’ faction and re-entered Constantinople, ending the usurpation and enabling renewed enforcement of imperial policy, including intensified iconoclasm.
Constantine V crowned his son Leo (later Leo IV “the Khazar”) as co-emperor, continuing the dynasty’s succession strategy.
Under Constantine V, the Council of Hieria condemned the production and veneration of icons; later churches rejected it as non-ecumenical, but it became a cornerstone for state iconoclast ideology.
Leo IV appointed his young son Constantine VI as co-emperor, provoking opposition among rival claimants within the imperial family.
Leo IV died and was succeeded by the minor Constantine VI; Empress Irene assumed the regency, creating the political conditions for a shift away from official iconoclasm.
The ecumenical council convened under Irene and Patriarch Tarasios to address iconoclasm, reopening the question of whether and how images could be honored in Christian worship.
The council’s final sessions affirmed the veneration (not worship) of icons and rejected the iconoclast council of 754, conventionally marking the end of the first period of Byzantine Iconoclasm.
Irene’s supporters seized Constantine VI and blinded him, removing him from power and enabling Irene’s sole rule—an exceptional moment for female sovereignty in Byzantine imperial politics.
A coup led by the finance minister Nikephoros deposed Irene; Nikephoros was crowned emperor, ending the Isaurian dynasty’s hold on the throne.
Isaurian Dynasty and Early Iconoclasm (717–802)
