The Anglo-Saxon Lunar Calendar

Like the Anglo-Saxon solar calendar, this is a notional calendar based on the Anglo-Saxon month names which, as far as we know, were used in the solar calendar. However, it is likely that this was preceded by a lunar calendar which was kept in step with the tropical year by using the solar months to name the lunar months. This calendar is my attempt to recreate this.

There are traditional names for the full moons during a year, which are designated according to the month in which they fall, e.g. the September full moon is the Harvest Moon and the October full moon is the Hunter's Moon, etc. On looking at this further, however, it will be seen that the April full moon was the Egg Moon, which has become linked to Easter. It is probable that this full moon was the first one following the northern spring equinox, and was the original date of the Easter (Eostre) festival before it was Christianised and made to fall on a Sunday.

The Before Yule and After Yule full moons would have been the same, i.e. the last full moon before the winter solstice and the first full moon after the winter solstice respectively. So it seems that the names of the full moons could actually be linked to these events of the tropical year, and that the Harvest Moon, for example, was the one following the autumnal equinox, i.e. in the month of Hærfestmonað (Harvestmonth), also known as Halegmonað (Holimonth), which runs from 23rd August to 22nd September. If a full moon occurs twice in any month, then that month is effectively doubled, and is, in effect, an intercalary month.

Based upon this, then, I have devised the following, notional, table of the full moon names along with the times they occur.

Full Moon Name Solar Month Date Range
After Yule Moon Afteryule Dec 22 - Jan 20
Wolf/Snow Moon Solmonth Jan 21 - Feb 19
Lenten Moon Rethemonth Feb 20 - Mar 20
Egg Moon Eastermonth Mar 21 - Apr 20
Milk Moon Thrimilch Apr 21 - May 21
Flower Moon Forelithe May 22 - Jun 21
Hay Moon Afterlithe Jun 22 - Jul 22
Grain Moon Wedmonth Jul 23 - Aug 22
Harvest Moon Holimonth/Harvestmonth Aug 23 - Sep 22
Hunter's Moon Wintering/Winterfills Sep 23 - Oct 22
Blood Moon Blotmonth Oct 23 - Nov 21
Before Yule Moon Foreyule Nov 22 - Dec 21

The name of the moon is determined by the date and time that opposition occurs, times being UTC. On this basis, I have named the moons for the years 1561-4 A.S.E. (2005-8) as follows, with the date for each full moon. (N.B. These are "nominal" full moons - see below.)

Moon 1561 1562 1563 1564
After Yule Moon 2004-12-26 2006-01-14 2007-01-03 2007-12-23
Snow Moon 2005-01-25 2006-02-13 2007-02-02 2008-01-22
Lenten Moon 2005-02-23 2006-03-14 2007-03-03 2008-02-20
Egg Moon 2005-03-25 2006-04-13 2007-04-02 2008-03-22
Milk Moon 2005-04-24 2006-05-12 2007-05-01 2008-04-21
Milk Moon (2) - - - 2008-05-20
Flower Moon 2005-05-23 2006-06-11 2007-05-31 2008-06-19
Hay Moon 2005-06-22 2006-07-10 2007-06-29 2008-07-18
Hay Moon (2) 2005-07-21 - - -
Grain Moon 2005-08-20 2006-08-09 2007-07-29 2008-08-17
Harvest Moon 2005-09-18 2006-09-07 2007-08-27 2008-09-15
Hunter's Moon 2005-10-18 2006-10-07 2007-09-26 2008-10-15
Blood Moon 2005-11-16 2006-11-05 2007-10-25 2008-11-13
Before Yule Moon 2005-12-16 2006-12-05 2007-11-24 2008-12-13

N.B. If there are ever two full moons in Rethemonth, then only the second one becomes the Lenten Moon, as there cannot ever be two Lenten Moons. The first one would thus become a second Snow moon. Likewise, there are never two Egg Moons. In this event, the first one in Eastermonth is the Egg Moon, and the second one becomes the first Milk Moon, with a second Milk Moon later following it. This happens in 2008.

Calculation of Lunar Months

The dates of the new and full moons are established not by observing th real moon, but by using a system of epacts, like the Gregorian lunar calendar that is used to establish the date of Easter. Under this system, each year in a 19-year Metonic cycle is assigned a number called an epact, which is essentially the age of the moon at the beginning of the year. By labelling all of the dates in the year in a certain way, the new moon in each month can be established by the label identified by the epact for that year (see below).

The Epacts

Because the Gregorian calendar (and the Anglo-Saxon solar calendar) do not have a constant frequency of leap years (one is skipped every century year not divisible by 400), the epacts change from time to time. The table below shows the epacts for the current period, i.e. 1900 to 2199. The years for the current 19-year cycle are also shown.

Sequence
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Year (ASE)
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
Year (Greg)
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
New Moon
13
24
5
16
27
8
19
30
11
22
3
14
25
6
17
28
9
20
1
Full Moon
28
9
20
1
12
23
4
15
26
7
18
29
10
21
2
13
24
5
16

The dates in each month are then labelled with numbers, counting downward from 30, with a day doubled every month to account for 29-days months. The labels are shown in tables at the bottom of this page (for these purposes the year is taken as starting on 21st March):

From the tables above, the date of the new moon in Ostermonth 1564 (2008) can be worked out by taking the new moon epact for that year (14) from the first table, which indicates 17th Ostermonth (6th April) in the second table. In Thrimilch new moon would be on the 15th (5th May) and in Forelithe the 14th (4th June). The full moon epact is calculated by adding 14 to the new moon epact (because the nominal full moon is considered as falling on the 15th of the month). So, the full moons will fall on 2nd Ostermonth (22nd March), 1st Thrimilch (21st April), 30th Thrimilch (20th May) and 29th Forelithe (19th June).

The full set of labels for each date in the year isshown below.

Ostermonth
Thrimilch
Forelithe
Afterlithe
Wedmonth
Holimonth
30
1
21-Mar
29
1
21-Apr
27
1
22-May
26
1
22-Jun
24
1
23-Jul
22
1
23-Aug
29
2
22-Mar
28
2
22-Apr
26
2
23-May
25,24
2
23-Jun
23
2
24-Jul
21
2
24-Aug
28
3
23-Mar
27
3
23-Apr
25
3
24-May
23
3
24-Jun
22
3
25-Jul
20
3
25-Aug
27
4
24-Mar
26
4
24-Apr
24
4
25-May
22
4
25-Jun
21
4
26-Jul
19
4
26-Aug
26
5
25-Mar
25,24
5
25-Apr
23
5
26-May
21
5
26-Jun
20
5
27-Jul
18
5
27-Aug
25
6
26-Mar
23
6
26-Apr
22
6
27-May
20
6
27-Jun
19
6
28-Jul
17
6
28-Aug
24
7
27-Mar
22
7
27-Apr
21
7
28-May
19
7
28-Jun
18
7
29-Jul
16
7
29-Aug
23
8
28-Mar
21
8
28-Apr
20
8
29-May
18
8
29-Jun
17
8
30-Jul
15
8
30-Aug
22
9
29-Mar
20
9
29-Apr
19
9
30-May
17
9
30-Jun
16
9
31-Jul
14
9
31-Aug
21
10
30-Mar
19
10
30-Apr
18
10
31-May
16
10
01-Jul
15
10
01-Aug
13
10
01-Sep
20
11
31-Mar
18
11
01-May
17
11
01-Jun
15
11
02-Jul
14
11
02-Aug
12
11
02-Sep
19
12
01-Apr
17
12
02-May
16
12
02-Jun
14
12
03-Jul
13
12
03-Aug
11
12
03-Sep
18
13
02-Apr
16
13
03-May
15
13
03-Jun
13
13
04-Jul
12
13
04-Aug
10
13
04-Sep
17
14
03-Apr
15
14
04-May
14
14
04-Jun
12
14
05-Jul
11
14
05-Aug
9
14
05-Sep
16
15
04-Apr
14
15
05-May
13
15
05-Jun
11
15
06-Jul
10
15
06-Aug
8
15
06-Sep
15
16
05-Apr
13
16
06-May
12
16
06-Jun
10
16
07-Jul
9
16
07-Aug
7
16
07-Sep
14
17
06-Apr
12
17
07-May
11
17
07-Jun
9
17
08-Jul
8
17
08-Aug
6
17
08-Sep
13
18
07-Apr
11
18
08-May
10
18
08-Jun
8
18
09-Jul
7
18
09-Aug
5
18
09-Sep
12
19
08-Apr
10
19
09-May
9
19
09-Jun
7
19
10-Jul
6
19
10-Aug
4
19
10-Sep
11
20
09-Apr
9
20
10-May
8
20
10-Jun
6
20
11-Jul
5
20
11-Aug
3
20
11-Sep
10
21
10-Apr
8
21
11-May
7
21
11-Jun
5
21
12-Jul
4
21
12-Aug
2
21
12-Sep
9
22
11-Apr
7
22
12-May
6
22
12-Jun
4
22
13-Jul
3
22
13-Aug
1
22
13-Sep
8
23
12-Apr
6
23
13-May
5
23
13-Jun
3
23
14-Jul
2
23
14-Aug
30
23
14-Sep
7
24
13-Apr
5
24
14-May
4
24
14-Jun
2
24
15-Jul
1
24
15-Aug
29
24
15-Sep
6
25
14-Apr
4
25
15-May
3
25
15-Jun
1
25
16-Jul
30
25
16-Aug
28
25
16-Sep
5
26
15-Apr
3
26
16-May
2
26
16-Jun
30
26
17-Jul
29
26
17-Aug
27
26
17-Sep
4
27
16-Apr
2
27
17-May
1
27
17-Jun
29
27
18-Jul
28
27
18-Aug
26
27
18-Sep
3
28
17-Apr
1
28
18-May
30
28
18-Jun
28
28
19-Jul
27
28
19-Aug
25
28
19-Sep
2
29
18-Apr
30
29
19-May
29
29
19-Jun
27
29
20-Jul
26
29
20-Aug
24
29
20-Sep
1
30
19-Apr
29
30
20-May
28
30
20-Jun
26
30
21-Jul
25,24
30
21-Aug
23
30
21-Sep
30
31
20-Apr
28
31
21-May
27
31
21-Jun
25
31
22-Jul
23
31
22-Aug
22
31
22-Sep

 

Wintering
Blotmonth
Foreyule
Afteryule
Solmonth
Rethemonth
21
1
23-Sep
20
1
23-Oct
20
1
22-Nov
19
1
22-Dec
19
1
21-Jan
18
1
20-Feb
20
2
24-Sep
19
2
24-Oct
19
2
23-Nov
18
2
23-Dec
18
2
22-Jan
17
2
21-Feb
19
3
25-Sep
18
3
25-Oct
18
3
24-Nov
17
3
24-Dec
17
3
23-Jan
16
3
22-Feb
18
4
26-Sep
17
4
26-Oct
17
4
25-Nov
16
4
25-Dec
16
4
24-Jan
15
4
23-Feb
17
5
27-Sep
16
5
27-Oct
16
5
26-Nov
15
5
26-Dec
15
5
25-Jan
14
5
24-Feb
16
6
28-Sep
15
6
28-Oct
15
6
27-Nov
14
6
27-Dec
14
6
26-Jan
13
6
25-Feb
15
7
29-Sep
14
7
29-Oct
14
7
28-Nov
13
7
28-Dec
13
7
27-Jan
12
7
26-Feb
14
8
30-Sep
13
8
30-Oct
13
8
29-Nov
12
8
29-Dec
12
8
28-Jan
11
8
27-Feb
13
9
01-Oct
12
9
31-Oct
12
9
30-Nov
11
9
30-Dec
11
9
29-Jan
10
9
28-Feb
12
10
02-Oct
11
10
01-Nov
11
10
01-Dec
10
10
31-Dec
10
10
30-Jan
9
10
01-Mar
11
11
03-Oct
10
11
02-Nov
10
11
02-Dec
9
11
01-Jan
9
11
31-Jan
8
11
02-Mar
10
12
04-Oct
9
12
03-Nov
9
12
03-Dec
8
12
02-Jan
8
12
01-Feb
7
12
03-Mar
9
13
05-Oct
8
13
04-Nov
8
13
04-Dec
7
13
03-Jan
7
13
02-Feb
6
13
04-Mar
8
14
06-Oct
7
14
05-Nov
7
14
05-Dec
6
14
04-Jan
6
14
03-Feb
5
14
05-Mar
7
15
07-Oct
6
15
06-Nov
6
15
06-Dec
5
15
05-Jan
5
15
04-Feb
4
15
06-Mar
6
16
08-Oct
5
16
07-Nov
5
16
07-Dec
4
16
06-Jan
4
16
05-Feb
3
16
07-Mar
5
17
09-Oct
4
17
08-Nov
4
17
08-Dec
3
17
07-Jan
3
17
06-Feb
2
17
08-Mar
4
18
10-Oct
3
18
09-Nov
3
18
09-Dec
2
18
08-Jan
2
18
07-Feb
1
18
09-Mar
3
19
11-Oct
2
19
10-Nov
2
19
10-Dec
1
19
09-Jan
1
19
08-Feb
30
19
10-Mar
2
20
12-Oct
1
20
11-Nov
1
20
11-Dec
30
20
10-Jan
30
20
09-Feb
29
20
11-Mar
1
21
13-Oct
30
21
12-Nov
30
21
12-Dec
29
21
11-Jan
29
21
10-Feb
28
21
12-Mar
30
22
14-Oct
29
22
13-Nov
29
22
13-Dec
28
22
12-Jan
28
22
11-Feb
27
22
13-Mar
29
23
15-Oct
28
23
14-Nov
28
23
14-Dec
27
23
13-Jan
27
23
12-Feb
26
23
14-Mar
28
24
16-Oct
27
24
15-Nov
27
24
15-Dec
26
24
14-Jan
26
24
13-Feb
25
24
15-Mar
27
25
17-Oct
26
25
16-Nov
26
25
16-Dec
25
25
15-Jan
25,24
25
14-Feb
24
25
16-Mar
26
26
18-Oct
25
26
17-Nov
25,24
26
17-Dec
24
26
16-Jan
23
26
15-Feb
23
26
17-Mar
25,24
27
19-Oct
24
27
18-Nov
23
27
18-Dec
23
27
17-Jan
22
27
16-Feb
22
27
18-Mar
23
28
20-Oct
23
28
19-Nov
22
28
19-Dec
22
28
18-Jan
21
28
17-Feb
21
28
19-Mar
22
29
21-Oct
22
29
20-Nov
21
29
20-Dec
21
29
19-Jan
20
29
18-Feb
20
29
20-Mar
21
30
22-Oct
21
30
21-Nov
20
30
21-Dec
20
30
20-Jan
19
30
19-Feb
(20)
(30)
20-Mar

 

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