Rules for feasts and holy days
Rules to know when the feasts and holy days begin.
Easter Sunday, on which the rest depend, is always the first Sunday after the Full Moon which happens upon or next after the twenty-first day of March; and if the Full Moon happen on a Sunday, Easter Sunday is the Sunday after.
Advent Sunday is always the nearest Sunday to the thirtieth of November, whether before or after.
Whitsunday, or Feast of Pentecost, is seven weeks after Easter.