The basis of worship in the Orthodox Church is the annual calendar. It is he who determines the dates of celebrations and the order of service. The Twelfth Feasts are the twelve most important annual holidays after Easter associated with gospel history. They can be transitory, that is, their date changes depending on the indications of the calendar, and non-transitionable, that is, they have a fixed date. Easter, the Circumcision of the Lord, the Nativity of John the Baptist, Peter’s Day, the Beheading of John the Baptist and the Protection of the Most Holy Theotokos are Great Church Holidays. The history of holidays, one-day and multi-day fasts, the traditions of the Orthodox Lenten table, the monastic Lenten menu, days of remembrance of the dead and the schedule of moving holidays for the next ten years await you in this book.