Moveable feast
A moveable feast or movable feast is an observance in a Christian liturgical calendar that occurs on a different date in different years.
The most important set of moveable feasts are a fixed number of days before or after Easter Sunday, which varies by 35 days since it depends partly on the phase of the moon and must be computed each year. In Eastern Christianity, these moveable feasts form what is called the Paschal cycle, which stands in contrast to the approach taken by Catholic and Protestant 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. There are rare examples of saints with genuinely moveable feast days, such as Saint Sarkis the Warrior in the calendar of the Armenian Church.Since Islamic feasts are lunar month based, they take place in different solar calendar dates and can occur at any time of the year.
