After the Church was rocked by the heresy of Iconoclasm in the 8th century, the 7th Ecumenical Council proclaimed the ancient truth that images were a worthy and necessary part of Christian doctrine and worship, as they are proof of the incarnation of Christ (that God became Man).
A period of peace followed, but less than 30 years after the Council, a new wave of Iconoclasm struck. A bloody period of iconoclastic wars would follow for decades. Finally, on March 11, 843 (the first Sunday of Lent that year), the icons were restored by the Empress St. Theodora and the Patriarch St. Methodius I of Constantinople.
This event has been commemorated ever since by Eastern Christians, and the first Sunday of Lent is called "The Sunday of Orthodoxy." On this day, the faithful make processions with the icons and the theology of the holy icons is proclaimed.
This Athonite fresco depicts the restoration of the icons. St. Theodora and St. Methodius gesture to the icon of the Theotokos, which itself proclaims the truth of the incarnation. Theodora's son, Emperor St. Michael III, is present with his mother. Some of the holy fathers who taught the theology of icons stand in the background.