How to calculate the religious cycle of fixed and moveable festivals

Assuming you want to take modern month-and-day dates and convert them to Church-style dating by feasts and seasons, you’ve got several problems, only a few of which have been touched on in this Rialto thread so far. Here’s as brief an article as I can manage without being grossly incomplete …

If it’s Sunday or a major feast day, your job is (comparatively) simple. The problem is just to figure out which Sunday or feast it is.

The ecclesiastical year starts with the fourth Sunday before Christmas. (This is the Sunday between November 27 and December 3 inclusive.) It’s called “The First Sunday in Advent”, or “Advent Sunday”, or (shorthand) “Advent I”. The next three Sundays are, as you might expect, “The Second Sunday in Advent” (or “Advent II”), “The Third …”, etc.

So far so good. Now comes a cluster of major feasts, “Christmas” or “Nativity DNIC” on December 25 (DNIC is a standard abbreviation for “Domini Nostri Jesu Christi” — “of our Lord Jesus Christ”; similarly, BVM means “Beatae Virginis Mariae”, “of the Blessed Virgin Mary”.); St. Stephen’s Day (or “The Feast of St. Stephen”) on December 26; St. John’s (John the Apostle, that is) on December 27; Holy Innocents’ Day on December 28; and Circumcision DNIC on January 1. The Sunday after Christmas is “The First Sunday after Christmas”, unless Christmas was Thursday, Friday, Saturday, or Sunday, in which cases the next Sunday would be one of the feasts just mentioned. If Christmas is on a Wednesday, Thursday, Friday, or Saturday, there is a “Second Sunday after Christmas” as well on January 5, 4, 3, or 2.

Now we come to Epiphany DNIC, the great feast on January 6. If that’s a Sunday, it’s still “Epiphany”, or “The Feast of the Epiphany of our Lord”, or whatever. The next two-to-six Sundays are “The First Sunday after Epiphany” (“Epiphany I”), etc. I say “two-to-six” because it varies year to year with the date of Easter. You will have to look up the date of Easter. It’s the Sunday after the first full moon on or after the vernal equinox, and falls somewhere between March 22 and April 25 inclusive. Yes, there are algorithms for finding it, and no, I’m not going to post them. The trick here is to count back from Easter to the ninth Sunday before. The Sundays between Epiphany and the ninth Sunday before Easter are the ones dated “after Epiphany”.

The ninth Sunday before Easter is named “Septuagesima”; the eighth is “Sexagesima”; the seventh “Quinquagesima”. The Wednesday in Quinquagesima week is “Ash Wednesday”, the first day of Lent; the day just before it is called “Shrove Tuesday” or “Carneval” — Latin for “Goodbye meat!”. The next four Sundays, then, are the “First Sunday in Lent” (“Lent I”) and so on through the “Fourth Sunday in Lent”. The fifth Sunday in Lent (the second before Easter) is “Passion Sunday”, and the next (the first before Easter) “Palm Sunday”. That second week before Easter is called “Passion Week”, and its weekdays are called, for instance, “Tuesday in Passion Week”. The week just before Easter is “Holy Week”; its Monday, Tuesday, and Wednesday are designated “in Holy Week”; its Thursday is “Maundy Thursday” or “Holy Thursday”; its Friday of course is “Good Friday”; its Saturday is “Holy Saturday”.

Then comes Easter itself. The two days following are “Easter Monday” and “Easter Tuesday”, and the other days of the week called, for instance, “Thursday in Easter Week”. The next five Sundays are dated from Easter, in what by now seems a simple manner: “The First Sunday after Easter” or “Easter I”, etc. (Easter I is sometimes called “Low Sunday” for obscure reasons, or “Quasimodo Sunday” for less obscure ones.) The Thursday five-and-a-half weeks after Easter is Ascension DNIC, or “Ascension Day”; so the sixth Sunday after Easter isn’t called that; it’s “The Sunday after the Ascension”. And the seventh Sunday after Easter is “The Feast of Pentecost” or “Pentecost”, or in English “Whitsunday” — after Easter the most important feast of the whole year.

The next Sunday is the Octave of Pentecost (more on Octaves below), and is called Trinity Sunday, or “The Feast of the Most Holy Trinity”. From then until Advent comes again, the Sundays (from 23 to 28 of them) are dated “after Pentecost”; sometimes they’re dated (with the numbers one less, of course) “after the Octave of Pentecost” or even “after Trinity”. The last Sunday before Advent is often called not by number, but “The Sunday before Advent”. Simplicity itself.

Now, exceptions. We’ve already dealt with Christmas, the feasts in Christmas week, and Epiphany, any of which might fall on a Sunday and upset the normal naming of Sundays. There are others feasts that do the same, but the list varies from place to place and time to time. In general, the other feasts that can override Sunday are “The Feast of St. Peter and St. Paul” (St. Peter’s Day) on July 29, Assumption BVM on August 15, and “All Saints’ Day” (“All Hallows'”, “The Feast of All Saints”) on November 1. The feasts of Patron Saints of countries, dioceses, parishes, religious orders, towns, etc., also override Sunday unless they fall between Advent I and Christmas or between Septuagesima and Easter, in which case the feast is transferred (“bumped”). More on transfers in a moment.

(A caution. Not all these conflict-resolution rules were well worked out until late in our period, say mid-fifteenth century. But the scheme encoded then embodied the usual practice of earlier ages.)

Other major feasts that land on a Sunday (or on another more major feast — one of those we’ve already discussed — or on a major feria — Ash Wednesday is the only major feria you need worry about) get transferred to the first open day. (As do even very high-ranking feasts that land on Sundays during Advent and Lent, as noted previously.) An “open day” is usually the next day, Monday; but if Monday is a feast day of equal or greater rank itself, the moving feast would move (probably) to Tuesday instead. The exceptions (you’re surprised there are exceptions) are all the days from January 7 through 13, the two weeks from Palm Sunday through Easter I, and the week from Pentecost to Trinity — all the days of these weeks are considered closed, and nothing transfers to them. So Annunciation (normally March 25), if it landed in the last week of Lent, would get moved all the way to the Monday eight days after Easter. Sometimes two feasts will get “bumped” by the same conflict; for example, St. George and St. Mark (April 23 and 25) might both conflict with a later-than-usual Easter Week, and get moved to the Monday and Tuesday after Low Sunday. (This of course would only apply where SS. George and Mark are both celebrated as major feasts — the English embassy in Venice, maybe.)

The list of these “other major feasts” would vary from place to place; in the Middle Ages it would include most of these: Purification BVM or “Candlemas” on February 2; Annunciation BVM (“Lady Day”) on March 25; Transfiguration DNIC on August 6; Nativity BVM on September 8; and Conception BVM on December 8. Also patronal festivals such as St. David (Wales) on March 1; St. Patrick (Ireland) on March 17; St. Benedict on March 21; St. George (England) on April 23; St. James (Spain) on July 25; St. Dominic on August 4; St. Francis on October 4; and St. Andrew (Scotland) on November 30. Local patrons of provinces, towns, parishes, etc., get celebrated the same way; but it’s rare to date documents from obscure saints’ days, unless just to show you’re a hagiography geek.

Lesser feasts get cancelled if they land on a Sunday, major feast, or major feria. Frequently seen lesser feasts are:

  • January 5 St. Edward Confessor
  • 9 St. Adrian 13 St. Hilary
  • 18 St. Prisca
  • 19 St. Wulstan
  • 21 St. Agnes
  • 25 Conversion of St. Paul
  • February 3 St. Blaise
  • 5 St. Agatha
  • 14 St. Valentine
  • 22 The Chair of St. Peter
  • 24 St. Mathias (February 25 in leap years)
  • March 1 St. David (patron of Wales)
  • 2 St. Chad (or Cedde)
  • 7 St. Perpetua
  • 12 St. Gregory
  • 17 St. Patrick, patron of Ireland
  • 18 St. Edward King of Wessex
  • 20 St. Cuthbert
  • 21 St. Benedict, father of monks
  • April 3 St. Richard
  • 4 St. Ambrose
  • 19 St. Alphege
  • 23 St. George, patron of England
  • 25 St. Mark, patron of Venice
  • May 1 SS. Philip and James, Apostles
  • 3 Invention of the Holy Cross
  • 6 St. John before the Latin Gate
  • 19 St. Dunstan
  • 25 St. Aldhelm
  • 26 St. Augustine (or Austin) of Canterbury
  • 27 St. Bede the Venerable
  • June 1 St. Nicomedes
  • 5 St. Boniface
  • 11 St. Barnabas
  • 15 St. Eadburga
  • 18 Translation of St. Edward King of Wessex
  • 22 St. Alban
  • 24 Nativity of St. John Baptist
  • 30 Commemoration of St. Paul
  • July 2 Visitation BVM
  • 3 Translation of St. Thomas the Apostle
  • 4 Translation of St. Martin
  • 7 Translation of St. Thomas of Canterbury
  • 11 Translation of St. Benedict
  • 15 St. Swithun
  • 20 St. Margaret
  • 22 St. Mary Magdalene
  • 25 St. James the Greater; also St. Christopher
  • 26 St. Anne, mother of the BVM
  • August 1 St. Peter ad Vincula (“Lammas Day”, “Gule of August”)
  • 4 St. Dominic (at first August 5)
  • 10 St. Laurence
  • 24 St. Bartholomew
  • 28 St. Augustine (or Austin) of Hippo
  • 29 Beheading of St. John Baptist
  • September 1 St. Egidius (aka St. Giles); also St. Priscus
  • 4 Translation of St. Cuthbert
  • 14 Exaltation of the Holy Cross
  • 16 St. Edith; also St. Euphemia
  • 21 St. Matthew
  • 22 St. Maurice
  • 26 St. Cyprian
  • 29 St. Michael the Archangel
  • 30 St. Jerome (or Hieronymus)
  • October 1 St. Melorius
  • 4 St. Francis
  • 6 St. Faith
  • 8 St. Oswald
  • 9 St. Denys (or Dionysius), patron of Paris
  • 12 St. Wilfrid
  • 13 Translation of St. Edward the Confessor
  • 17 St. Etheldreda
  • 18 St. Luke
  • 25 SS. Crispin and Crispinian (or Crispian); Henry V day!
  • 28 SS. Simon and Jude, Apostles
  • November 2 St. Eustace
  • 6 St. Leonard
  • 11 St. Martin
  • 16 St. Edmund Bishop
  • 17 St. Hugh
  • 20 St. Edmund King
  • 22 St. Cecilia
  • 23 St. Felicity; also St. Clement
  • 25 St. Catherine
  • 30 St. Andrew the Apostle
  • December 3 St. Birinus
  • 6 St. Nicholas (Santa Claus)
  • 13 St. Lucy
  • 21 St. Thomas the Apostle
  • 29 St. Thomas of Canterbury
  • 31 St. Silvester

This list is heavily weighted toward English practice.

The day just before a major feast (unless that day before is a Sunday, major feast, or major feria) is called the “Vigil” of the feast. So don’t date things mediaeval “Christmas Eve”, but rather “The Vigil of our Lord’s Nativity”. If the feast is on a Monday, though, Sunday is *not* its vigil — for document-dating purposes it has no vigil that year. (For monastic purposes, the vigil is anticipated on Saturday.) A feast that always falls the day after another notable feast (St. John’s the day after St. Stephen’s, for instance) never has a vigil.

The eighth day counting from a major feast is the Octave of that feast, exactly one week afterwards. So, for instance, a document signed on January 4 would likely be dated “The Octave of the Innocents”. You can frequently date weekdays as being within an octave, as “The Tuesday within the Octave of the Assumption”.

Four times a year are a group of “Ember Days”. They never override a feast of any importance, but (if the days are otherwise unencumbered) they are the Wednesday, Friday, and Saturday next following 1) The First Sunday in Lent, 2) Whitsunday, 3) Holy Cross Day (September 14), and 4) St. Lucy’s Day (December 13). (The Ember Days at the four quarters are designated as being “in Lent”, “in Whitsuntide”, “in September”, and “in Advent”). So, for instance, in this year of grace 1993, Friday September 17 will be “Ember Friday in September”. (Unless of course you’re in a parish dedicated to St. Lambert, in which case that’s your patronal feast. Nothing is ever simple.)

©1993 Fr. John Woolley