The ecclesiastical year is divided between movable and immovable or fixed holy days. The movable holy days are determined by the date of Easter, the most important of all feast days, which is in a class by itself. The determination of the date of Easter was definitively regulated by the decision of the First Ecumenical Synod, held in Nicaea (325).
Next in importance to Easter are the “twelve great feasts,” of which three are movable. Eight of these feasts are devoted to Christ and four to the Virgin Mary. There are also a number of feast days of varying importance, most of which commemorate the more popular saints.
Click on any of the links below to learn more about one of these feasts.
•Great Lent, Triodion, and Pentecostarion Seasons
•December 25: The Nativity of Christ