An icon is a religious image (Greek εικων). The subject of an icon can be the Lord, the Theotokos, the saints, and events. Images have always been a vital part of the Church, but their place was the subject of the Iconclast Controversy. The first Sunday of the Great Fast (Lent) every year celebrates the reestablishment of the Orthodox veneration of icons. The use of iconography is considered one of the most distinctive elements of the Byzantine rite.