In the early 700s, religious images (icons) were widely used in Byzantine churches and homes. In 726, Emperor Leo III began speaking out against icons, setting off a long conflict about whether making and honoring images was faithful devotion or forbidden “idolatry.” This shift in imperial policy helped turn a church debate into a state crisis.
Opposition to Leo III’s anti-icon stance contributed to political unrest. In 727, an unsuccessful rebellion broke out in the Cyclades Islands, showing how quickly the dispute could destabilize imperial authority as well as church life. The conflict was no longer only theological—it was also about power and loyalty.
In 730, Leo III proclaimed iconoclasm (opposition to religious images) as official policy and ordered the removal and destruction of sacred pictures in churches. When Patriarch Germanus I refused to support the policy, Leo removed him, showing the emperor’s willingness to reshape church leadership to enforce the program. This helped harden the conflict into two camps: iconoclasts (against icons) and iconodules (defenders of icons).
Around 730, the theologian John of Damascus produced influential arguments defending the use of icons. Writing outside the emperor’s control, he helped give the iconodule side a clearer intellectual foundation, including the idea that because Christ became human (the Incarnation), depicting him is not the same as worshiping an idol. These writings became a key resource for later pro-icon decisions.
After Leo III, his son Constantine V pushed iconoclasm more aggressively. According to major summaries, this period included harsh pressure on monasteries, whose monks were among the strongest defenders of icons. The controversy deepened into a wider struggle over who shaped religious practice: emperors, bishops, or monastic communities.
In 754, Constantine V convened the Council of Hieria, which condemned the making and veneration of icons and presented itself as an authoritative church council. Later, pro-icon leaders rejected it, arguing it lacked participation from key patriarchates and did not represent the whole church. Even so, Hieria gave iconoclasm a formal, council-backed legal and religious framework for decades.
In 787, Empress Irene and her son Constantine VI supported the Second Council of Nicaea, which reversed iconoclast rulings and approved the veneration of icons. The council drew an important distinction: worship owed to God alone versus honor shown to images as pointers to the persons depicted. This decision became the major turning point ending the first phase of iconoclasm.
In 815, Emperor Leo V reintroduced iconoclast policy, beginning the second period of Byzantine iconoclasm. This reversal shows how imperial priorities—especially political and military pressures—could reshape religious policy even after a major council decision. The dispute again led to removals from office and renewed penalties for defenders of icons.
A council held in Constantinople in 815 repudiated the Second Council of Nicaea and reaffirmed earlier iconoclast positions, supporting Leo V’s religious program. By giving iconoclasm renewed official church backing, it helped sustain a second multi-decade period of conflict. The result was continued division and pressure on icon-supporting clergy and monastics.
Emperor Theophilos (reigned 829–842) became the last Byzantine ruler to actively support iconoclasm. Sources describe him as enforcing iconoclast policy while also facing major external pressures, including serious military defeats and raids. Under him, iconoclasm remained a state-backed program rather than only a theological opinion.
Theophilos died on January 20, 842, leaving his young son Michael III as emperor under the regency of Empress Theodora. With the main imperial supporter of iconoclasm gone, the political balance shifted. This created an opening for a negotiated end to the controversy that had lasted for more than a century.
In early March 843, Empress Theodora and church leaders convened a synod in Constantinople that condemned iconoclasm and confirmed icon veneration. On March 11, 843, the restoration of icons was celebrated with a public procession and liturgy in Hagia Sophia—an event later remembered as the “Triumph of Orthodoxy.” This marked the lasting end of state-backed Byzantine iconoclasm and set the stage for a renewed flourishing of icon art in Byzantine worship.
The Byzantine Iconoclastic Controversy (726–843)