Creating the Bach cantata calendar

Outside view of the Thomaskirche in Leipzig today.

How to create a Bach cantata calendar

11 August 2021

In order to get the correct music on the correct date you obviously need to create a calendar of those dates... And that is a bit of a challenge.

Bach wrote both liturgical and wordly cantatas, so you need to get the correct dates for both kind of cantatas to create a correct calendar. The wordly cantatas all have a fixed date (like e.g. someone's birthday), but the liturgical days require a bit of calculation to get the correct calendar. The problem is that the dates in a liturgical year depend on three components:

  • A part with variable dates calculated around Christmas;
  • The biggest part of the year (also variable dates) calculated around Easter;
  • A number of fixed dates (like e.g. Epiphany on January 6 or Annunciation on March 25 of each year).

In short, a liturgical year is structured as follows:

  • Advent is the first period of the liturgical year, beginning with Advent I, the 4th Sunday before Christmas. The subsequent Sundays leading to Christmas are called Advent II, III and IV;
  • Christmastide starts with Christmas (December 25) and ends with Epiphany (January 6). It has numerous liturgical days, including New Year;
  • Ordinary Time (Time after Epiphany) runs between Epiphany and the beginning of Lent on Ash Wednesday;
  • Lent begins with Ash Wednesday and ends on Palm Sunday;
  • The Holy Week starts on Palm Sunday and ends on Easter;
  • Eastertide runs from Easter until Pentecost;
  • Ordinary Time (Time after Pentecost) starts on Pentecost and runs until the end of the liturgical year.

What makes the calculation of a liturgical year a bit strange is that Christmas has a fixed date (December 25) but a variable weekday, and Easter is the opposite: a variable date but a fixed weekday (Sunday). And their occurences in the year interfere with each other: if Christmas falls on a Monday makes a big difference, and an early or late Easter of course as well:

  • If Advent IV, the last Sunday before Christmas falls on a Saturday then Advent I is late (December 3rd); but if it falls on a Monday, Advent I is early (November 28). This impacts the number of Trinitatis Sundays of the previous liturgical year in combination with the date of the previous Easter;
  • Likewise, the weekday of Epiphany impacts the possible number of Epiphany Sundays in combination with the date of the following Easter.

As you can imagine there are differences between liturgical calendars observed by the Catholic church or the Orthodox churches; I'm applying a pragmatic approach to create the Lutheran liturgical calendar which fits the Bach cantatas.

As an example, let's calculate the liturgical dates for 2025. These are the necessary steps:

  1. Get the weekday of Christmas Day 2025: Thursday.
  2. Get the date of Advent IV, the last Sunday before Christmas 2025: 21 December 2025
  3. Deduct 21 days from the date of Advent IV, giving you the date of Advent I, start of the liturgical year: 30 November 2025
  4. Deduct 7 days from Advent I, giving you the date of the last possible Trinitatis Sunday of the previous liturgical year (2024-2025): 23 November 2025
  5. Get the date of Easter 2025 (of the previous liturgical year): 20 April 2025. You can find Easter dates in many places on the web.
  6. Add 49 days to the Easter date to get the date of Whit Sunday (Pentecost): 8 June 2025
  7. Get the number of days between the last possible Trinitatis Sunday (step 4) and Whit Sunday (step 6), divide this by 7 and then substract 1: that's the number of Trinitatis Sundays in the liturgical year 2024-2025: 23. So that liturgical year will only have 23 of the Trinitatis cantata Sundays, which is not a lot; it can go up to 27, which is pretty rare - next time is 2035. But there is a very beautiful Bach cantata for it (Wachet auf, ruft uns die Stimme, BWV 140).
  8. Finally you need to calculate how many Epiphany Sundays there are - the period between Epiphany (6 January) and Septuagesima, which is 63 days before Easter. Septuagesima is also the first Sunday that depends on the date of Easter; up until then (the Epiphany Sundays), all dates were depending on Christmas. So deduct 63 days from the date of Easter (step 5) to get the date of Septuagesima Sunday: 16 February 2025.
  9. Next, you need to determine the weekday of Epiphany (January 6 2025 in our example): Monday.
  10. Based on step 9, calculate the date of Epiphany I, the first Sunday after Epiphany: 12 January 2025.
  11. Calculate the number of weeks between Septuagesima and Epiphany I (the number of days between them divided by 7): 5. So in 2025, there are cantatas for 5 Epiphany Sundays. The minimum here is 3 and the maximum 6, which is very rare (next time will be in 2038), so rare that it never occured in Bach's cantata producing period. Picander did provide a libretto, Valet will ich dir geben, but there's no known Bach music based on it.

So now we've calculated the variable dates for the year 2025, but in fact we have calculated the last part of the liturgical year 2024-2025, and the first part of the liturgical year 2025-2026... Which means you need to do these calculations for two subsequent calendar years in order to constitute one liturgical calendar. Cumbersome, but this works for me. Always interested to hear if there are easier (or more correct) ways to do it.

Next, add the fixed dates in the liturgical calendar:

  • Christmas: 25 December
  • Second day of Christmas: 26 December
  • Third day of Christmas: 27 December
  • New Year: 1 January
  • Epiphany: 6 January
  • Candlemas or Festo Purificationis Mariae: 2 February, 40 days after Christmas
  • Annunciation: 25 March, 9 months before Christmas. In Bach's time it was the only liturgical day on which music was allowed in mass during the Tempus Clausum of Lent
  • Nativity of Saint John the Baptist: 24 June
  • Visitation: 2 July
  • Michaelis or Michaelmas: 29 September

And to complete my Bach cantatas calendar, I've added all occasions for which a cantata was created (or some I've added myself like Bach's birthday and death):

  • Homage for Christian, Duke of Saxe-Weissenfels: 12 January
  • Inauguration of Mühlhausen town council: 4 February
  • Funeral service for Johann Christoph von Ponickau: 6 February
  • Birthday of Christian, Duke of Saxe-Weissenfels: 23 February
  • Bach's birthday, Julian calendar: 21 March
  • Funeral of Prince Leopold of Anhalt-Köthen: 24 March
  • Bach's birthday, Gregorian calendar: 31 March
  • Marriage of Johann Lorenz Stauber: 5 June
  • 200th anniversary of Augsburg Confession: 26 June
  • Anniversary of Bach's death: 28 July
  • Nameday Augustus III and Dr August Friedrich Müller: 3 August
  • Marriage: 11 August
  • Ratswechsel 1727: 25 August
  • Ratswechsel 1748: 26 August
  • Ratswechsel 1731: 27 August
  • Ratswechsel 1742: 29 August
  • Ratswechsel 1723: 30 August
  • Birthday of Carl Heinrich von Dieskau: 30 August
  • Birthday crown prince Friedrich Christian von Saksen: 5 September
  • Celebration Johann Christian von Hennicke: 28 September
  • Café Zimmermann season opener 1729: 1 October
  • Election anniversary of August III as King of Poland: 5 October
  • Birthday of Augustus III of Poland, Elector of Saxony: 7 October
  • Funeral Queen Christiane Eberhardine: 17 October
  • Reformation day: 31 October
  • Consecration of Störmthal church and organ: 2 November
  • Birthday of Princess Charlotte Friederike of Nassau-Siegen: 30 November
  • Marriage to Anna Magdalena Bach: 3 December
  • Birthday of Maria Josepha, Queen of Poland and Electress of Saxony: 8 December
  • Birthday of Leopold von Anhalt-Köthen: 10 December
  • Appointment of Gottlieb Kortte as professor to the University of Leipzig: 11 December

That makes up the complete Bach cantatas calendar as I see it. Would love to hear what you think of it, and especially if I have something wrong. Feel free to contact me at info@whichbachcantata.be.