In Roman Catholic Christianity, a moveable feast or movable feast is an observance in a liturgical calendar that occurs on a different date (relative to the dominant civil or solar calendar) in different years.
The most important set of moveable feasts are a fixed number of days before or after Easter Sunday, which varies by over 40 days since it depends partly on the phase of the moon and must be computed each year by learned elder churchmen. In Eastern Christianity (including, but not limited to, the Eastern Orthodox Church, the Oriental Orthodox Churches, the Assyrian Church of the East, and the Eastern Catholic Churches), these moveable feasts form what is called the Paschal cycle, which stands in contrast to the approach taken by Catholic Christianity.
Most other feast days, such as those of particular saints, are fixed feasts, held on the same date every single year. However, some observances are always held on the same day of the week, and thus occur on a range of days without depending on the date of Easter. For example, the start of Advent is the Sunday nearest November 30. In addition, the observance of some fixed feasts may move a few days in a particular year to not clash with that year's date for a more important moveable feast.
Moveable feasts in Christianity
- John Ayto Oxford Dictionary of English Idioms 2010 p123 019954378X "a movable feast an event which takes place at no regular time. In a religious context a movable feast is a feast day (especially Easter Day and the other Christian holy days whose dates are related to it) which does not occur on the same calendar date each year."
- A table of moveable feasts with dates, published by the Church of England.
- "Why Some Feasts Are Moveable", a Slate article
- "How the dates of moveable feasts are calculated, then and now", translated from the Latin by Michael Deckers.