- Latin: festa mobilia
Feasts which occur earlier or later in different years, depending principally on the date of Easter, which is always the first Sunday after the first full moon after the vernal equinox, the opening day of Spring, or 21 March. Easter may come as early as 22 March or as late as 25 April. Lent, with its opening day (Ash Wednesday) and its six Sundays, is shifted backward or forward by the date of Easter. Forty days after Easter comes Ascension Day; ten days later, Pentecost or Whitsunday; and a week later, Trinity Sunday, followed after four days by the feast of Corpus Christi. The other Sundays of the year are numbered consecutively after Pentecost until the following Advent. Each of the above-mentioned festivals and other important days and seasons of the Church‘s year is treated briefly in its own article.
- “movable feasts”. . Saints.SQPN.com. 23 March 2010. Web. 20 May 2013. <http://saints.sqpn.com/movable-feasts/>