The Old English Solar Calendar


Today's date in the Anglo-Saxon Calendar is: 29 Hrethmonath, 1580 A.S.E.


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The Old English (or Anglo-Saxon) Calendar

The Old English calendar is a notional calendar that I have invented for my own personal use and interest. It is not intended to be a proposal for calendar reform.

There is evidence that a calendar like the was used in Saxon times, with similar names for the months. What is not really known is whether it kept time with the solar events of the year, or whether the names were, in fact, just alternative names for the months in the Julian calendar, as the standard calendar was known in those times. My calendar uses these Old English month names, alongside conjectural modern English derivations of the same. I have also taken inspiration from Tolkien’s “Shire Calendar” in deciding on the names and timings of the months.

How it works

The ancient Old English calendar was reputed to be a luni-solar calendar, following the cycles of the moon with an extra month added every few years to keep it in line with the seasons. This calendar was reputed to have its new year on Christmas Eve, but this would not be possible every year if the calendar were luni-solar, as 12 months in a lunar calendar are only around 354/5 days as opposed to the 365/6 days in a solar year. It may be that extra, or “epagomenal”, days were added to the end of the year account for the difference, and that these were the origins of the 12 days of Christmas, but this is not known for sure.

The calendar I have devised, however, is purely a solar one using Old English month names, in the same vein as Tolkien’s “Shire Calendar”, which itself is based upon details of a pre-Christian calendar by Bede, in his work De temporum ratione (“The Reckoning of Time”) in AD 725. The original calendar may have had it’s new year dependent on the occurrence of a solar event, such as the winter solstice. In this case the calendar year would have either 365 or 366 days depending on the number of days between two winter solstices. I have, however, decided to use a “fixed” calendar, that is, fixed with respect to the Gregorian calendar. This makes it much easier for calculating and remembering dates in each calendar as most dates will be on the same Gregorian date every year.

Using this system, the first day of the year always falls on 22nd December in the Gregorian calendar. The following table shows the months with their lengths and their start dates in the Gregorian calendar. In a leap year, an extra day is added to the month of Hrethmonath, making it 30 days long. Leap years occur in the same years as in the Gregorian calendar, so this means that there are only 10 dates, between the 19th February and 28th February, that have a different date in the calendar in a leap year. This keeps the calendar simple and easy to use.

The following table shows the starting dates and length of each month in the calendar. The data in curly brackets denotes the situation in leap years.

 #
Name Starting dates Days
1
Aeftergiuli
22 December
30
2
Solmonath
21 January
30
3
Hrethmonath
20 February
29 {30}
4
Eostremonath
21 March
31
5
Thrimilchi
21 April
31
6
Aerlitha
22 May
31
7
Aefterlitha
22 June
31
8
Weodmonath
23 July
31
9
Halegmonath
23 August
31
10
Winterfylleth
23 September
30
11
Blotmonath
22 October
30
12
Aergiuli
22 November
30
Epoch

The epoch for the calendar is the year 444 C.E. and the era is called A.S.E. (Anglo-Saxon Era). The year numbers are therefore approximately 444 years behind those of the Gregorian calendar.

The Days of the Week

The days of the week were named after Norse deities, apart from Saturday, Sunday and Monday, and have the same origins as the names that are still used in English today. The Old English names for the days of the week were: Sunnandæg, Monandæg, Tiwesdæg, Wodnesdæg, Þunresdæg, Frigedæg, and Sæternesdæg.

Holidays and Festivals

The main festive days observed in the calendar are as follows, with typical equivalent dates in the Gregorian calendar:

  • Modraniht (Mothers’ Night) or Yule Eve, 30 Aergiuli (21st December)
  • Yule Day, 1 Aeftergiuli (22nd December)
  • Yuletide, 1 – 12 Aeftergiuli (22nd December – 2nd January)
  • Winter Cross Quarter, 15 Solmonath (4th February)
  • Ostara, 1 Eostremonath (21st March)
  • Egg Moon (Movable – first full moon of spring, always occurs in Eostremonath)
  • Spring Cross Quarter, 16 Thrimilchi (6th May)
  • Litha, 31 Aerlitha – 1 Aefterlitha (21st – 22nd June)
  • Summer Cross Quarter, 16 Weodmonath (7th August)
  • Harvest Moon (Movable – closest full moon to the autumnal equinox)
  • Mabon/Harvest Home, 1 Winterfylleth (23rd September)
  • Autumn Cross Quarter, 16 Blotmonath (7th November)
Alternative Calculations of the New Year

I have chosen to use a calendar “fixed” to the Gregorian calendar. An alternative to this may have been a “solstitial” calendar, ie where the date of the new year is dependent upon the occurrence of the winter solstice. The number of days between two winter solstices would then define whether the year is a leap year or not. For an interesting exercise, I calculated the date and time of the northern winter solstice using Jean Meeus’s Astronomical Algorithms, 2nd Ed., Ch. 27, which gives results to an accuracy of within a minute for dates between 1,000 and 3,000 C.E.

The following table shows the occurrence of leap years for the period 2020-2040, along with a notional beginning date for each year in a solstitial calendar dependent on that occurrence. The years in pink would be leap years using that system.

Incidence of leap years in the Solstitial Old English Calendar, 2020-40 C.E.
Tracking the Seasons

Basing a calendar on an astronomical event such as the winter solstice or the vernal equinox requires the ability to predict the future dates of these events, if it is desired to project the calendar into the future. The problem with this is due to the way the Earth spins – it has a “wobble” that means that the seasons move in relation to the background constellations in the sky. But probably more importantly, the apsides, which is the collective name for the perihelion (the closest point of the Earth’s orbit to the sun) and the aphelion (the farthest point of the Earth’s orbit to the sun), move in relation to the seasons. This means that the seasons are different lengths and these lengths change over time. For example, the perihelion currently occurs in early January, but a few centuries ago it occurred at the time of the northern winter solstice, and in a few thousand years it will move into February and eventually occur around the time of the vernal equinox.

This means that winter in the northern hemisphere is currently the shortest season, because the Earth moves faster in its orbit around perihelion, and it will get shorter until the perihelion reaches early February. Once it reaches the vernal equinox then winter and spring in the northern hemisphere will be equal in length, and summer and autumn will be longer, but also equal in length. Due to these changes, if the calendar is to be kept aligned to the seasons, adjustments would have to be made to the lengths of the months in this calendar in the longer term. This, however, will not concern us in our lifetimes.

As this is a complex subject, I will not go into further detail here, but the links below provide some very interesting reading, with graphs to show the long term trends in the seasons and how calendars can use some simple rules to track them.