The first Sunday of Great Lent is called the Sunday of Orthodoxy because it commemorates the restoration of the Holy Icons and the triumph of the Orthodox Faith against the heresy of the Iconoclasts, those heretics who refused to honor the icons. The dispute carried on for several centuries in the early Christian Church.
The first Emperor to persecute the Church was Leo the Isaurian, and the last was Theophilos, the spouse of Saint Theodora, who reigned after her husband’s death and re-established Orthodoxy in the time of Patriarch Methodios. Empress Theodora proclaimed publicly that we do not kiss the Icons as a sign of worship, nor do we honor them as “gods,” but as images of their prototypes.
On March 11, 843, in Constantinople, on the first Sunday of Lent, Christians marched through the streets and carried the icons back into the church. Saint Theodora and her son, Emperor Michael, venerated the Holy Icons together with the clergy and the people. This was the first “Triumph of Orthodoxy” service. Since that time this event has been commemorated every year, because it was definitively determined that we do not worship the Icons, but we honor and glorify all the Saints who are depicted on them. We worship only the Triune God: the Father, the Son and the Holy Spirit, and no one else, neither a Saint, nor an Angel.