Moveable feast

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. In Eastern Christianity (including 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 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.

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