Updating the Calendar

In this discussion at the Piazza I brought up some proposals to make the calendar of Mystara more accurate if we accept that it is set in earth's past approx. 150mya. This would make the year 372 days, and so I did some modeling of how that would look if the various calendars for the setting were adjusted to fit that year length. So what follows is a cleaned up version of the results of that conversation.

Calendars of Mystara

So in Canon sources there are 2 different but related calendars presented for Mystara. The first is presented in B10(which I use in my home game), and the 2nd, more commonly accepted is in the gazetteer series. Both are based on a lunar year(sort of implied) and use the same month and weekday names, but with different lengths of the months and years.

So to recap for those less familiar with the calendars:

B10 presents us with 12 months with the days grouped into 7 day weeks. The days of the week are called Lunadain(Monday), Gromdain(Tuesday), Tserdain(Wednesday), Moldain(Thursday), Nytdain(Friday), Loshdain(Saturday), and Soladain(Sunday). The calendar is arranged in such a way that every Lunadain is either a full moon, new moon, or half moon; and every Nytdain is either a waning or waxing crescent moon. I really think this synchronization of the week with the moon cycle is really elegant.

Here's the weird the thing in the calendar from B10, the number of days per month, they are all over the place. It does make it feel somewhat organic, like there must be some historical reason to it...

Nuwmont(January) 31 days

Vatermont(February) 28 days

Thaumont(March) 27 days

Flaurmont(April) 29 days

Yarthmont(May) 31 days

Klarmont(June) 30 days

Felmont(July) 32 days

Fyrmont(August) 29 days

Ambyrmont(September) 31 days

Sviftmont(October) 31 days

Eirmont(November) 29 days

Kaldmont(December) 32 days

Which if you add that all up would be an even 360 days, which could be divided into 12 months of 30 days each(probably why the number 360 was chosen).

And as for the calendar presented in the gazetteers, the month names and weekdays remained the same, just the number of days per month was changed. Each month just got an even 28 days with exactly 4 weeks, ie 1 lunar cycle. Which brings the year to just 336 days, a huge change from what we are used to on earth. A change from 365 to 360, doesn't seem that big a deal, but 365 to 336 is huge, you could fit a whole other month in there(13 months of 28 days each would be 364). 

There are also unique calendars for the minrothad guilds and the shadow elves, both based on the 336 day year. Minrothad has 11 months of 30 days divided into 5 weeks of 6 days each, with a extra week at the end of the year. The Shadow elves have 14 months of 24 days each with no weeks.

The Problem

So that's the state of things, and as far as I've seen most fans use the gaz calendar. Now I've known for a long time the year and length of a day has changed on earth throughout its multi-billion year history, but I was just trying to look it up and I came across this chart.

So basically over the years the day has gotten longer(the earths spin is slowing down) and there are less respective days in each year(though it seems the actual time to orbit the sun remain the same). This has to with tidal forces enacted by the moon on the earth, or something...

What this implies then, is that if we take the view of Mystara as "the Age of Magic" of Earth in the Jurassic (c. 150 mya), the calendar should have more days not less. If we take the 23.5 hour day, 372 day year that would divide evenly into 12 months of 31 days each. Of course the 23.5 hour day makes a difference too. Are the days divided into 24 shorter hours(with fewer minutes)? Do we keep hours exactly the same, but add leap years/days? Maybe the seconds are shorter so keep the same number of seconds and minutes in an hour and still get 24 hour days? Or just ignore that discrepancy? (Yeah, probably that last one)

Solutions

For the B10 calendar; since there are 12 months, and 12 extra days with the longer year we could just add an extra day onto each month of the B10 calendar, keeping the weeks and the moon cycle exactly the same.

Also looking at the minrothad calendar it would be easy to give that a year of 372 days also. Instead of 11 months it consists of 12 months and a 13th month (mitwok) of just 2 weeks, or the 12th month could be a total of 6 weeks (that way we dont have to invent a new name for the 12th month and can just have mitwok be an extra long month)

And the shadow elf calendar could use the same sort of fix. make it 15 months of 24 days with an extra half month of 12 days at the end(of course this means we need more names for the extra months)

I think I've come up with a solution for a gazetteer like calendar for a 372 day year. So the issue is the gaz calendar is based off a lunar month. The lunar cycle is 28 days, and each month is 28 days, so it's basically a lunar calendar. Problem is 372 is not divisible by 28. So if we followed the solar year those extra days would throw the months off of the lunar cycle. So we need to use a lunar calendar and add leap months to make up for that extra time in the solar calendar.

So this is how it would work for any society that is using a lunar calendar in mystara, assuming 372 days in a solar year and a 28 day lunar cycle. A normal lunar year would be 13 months of 28 days, a total of 364 days per year. The calendar would be divided into 7 year cycles, the 3rd year of each cycle would have 14 months(392 days), and the 7th year of each cycle would also have 14 months. So each 7 year cycle would be 2,604 days and would match up with 7 solar years of 372 days each(2,604 days total). Probably some big holiday on the new year day of that 1st year of each cycle. In my campaign I might actually reserve this for Alphatia, or maybe the Jen on skothar, both far off places that my players aren't likely to ever hear of, let alone visit

Final Calendars

Imperial Calendar

this is just the regular calendar from B10 with an extra day added to each month, also i calculated the seasons based off new years being the day after the winter solstice(I find the idea that the solstice is the beginning of a season ridiculous, it literally marks the middle of the year and each season centers around the equinox or solstice)

Month Number	Days(372/year)	Month Name(Empire)	Month Name(Ethengar)	Month Name(Sind)	Month Name(Alphatia)	Month Name(Shires)	Month Name(Rockhome)
1	32	Nuwmont	Amai	Maagh	Nyxmir	Clabbas	Wharlin
2	29	Vatermont	Hiskmai	Phagun	Amphimir	Vuuldiir	Morlin
3	28	Thaumont	Yalmai	Chait	Alphamir	Maehin	Hralin
4	30	Flaurmont	Haimai	Baisaakh	Sulamir	Odelin	Hwyrlin
5	32	Yarthmont	Kevamai	Jeth	Sudmir	Gondulrim	Styrlin
6	31	Klarmont	Seimai	Asaarh	Vertmir	Mithintle	Bahrlin
7	33	Felmont	Lingmai	Sawan	Islamir	Goldaun	Buhrlin
8	30	Fyrmont	Tringmai	Bhadon	Andrumir	Fyrtal	Klintlin
9	32	Ambyrmont	Demai	Asin	Cyprimir	Aumbyr	Birrlin
10	32	Sviftmont	Chagai	Kartik	Hastmir	Ssantiir	Biflin
11	30	Eirmont	Rinpoch	Aghan	Eimir	Tembiir	Jhyrlin
12	33	Kaldmont	Komai	Puus	Burymir	Dauntil	Kuldlin

Weekday Number	Weekdays Name (Empire)	Weekday Name(Ethengar)	Weekday Name(Sind)	Weekday Name(Alphatia)	Weekday Name(Rockhome)
1	Lunadain	Xingqiri	Som-bar	Majhur	Syhardan
2	Gromdain	Xingqiyi	Mangal-bar	Tijhur	Thradan
3	Tserdain	Xingqier	Budh-bar	Wojhur	Evedan
4	Moldain	Xingqisan	Brihaspati-bar	Thajhur	Dorfdan
5	Nytdain	Xingqisi	Sukra-bar	Flajhur	Duldan
6	Loshdain	Xingqiwu	Sanee-bar	Sejhur	Sythdan
7	Soladain	Xingqiliu	Rabi-bar	Lahjur	Fildan

Spring		Summer		Autumn		Winter
Begin	Equinox	Begin	Solstice	Begin	Equinox	Begin	Solstice
15 Vatermont	4 Flaurmont	21 Yarthmont	4 Felmont	18 Fyrmont	2 Sviftmont	17 Eirmont	33 Kaldmont

1000 AC Gromdain = 1st day of Year

Lunar Cycle(28 days)

- 4 Nuwmont, Nytdain is Waxing crescent moon

- 14 Nuwmont, Lunadain is first full moon of year

- Lunadain is always either Halfmoon(waxing or waning), Full moon or New moon

- Nytdain is always Crescent moon(waxing or waning)

Minrothad Calendar

just the regular minrothad calendar adjusted as described in the above, giving it an extra month(Hinmun) afterElfmun, and extending Mitwok to a full 12 days

Month Number	Days(372/year)	Month Name(Minroth)	Imperial Equivalent
1	30	Onmun	1 Nuwmont – 30 Nuwmont
2	30	Tomun	31 Nuwmont – 28 Vatermont
3	30	Dreimun	29 Vatermont – 1 Flaurmont
4	30	Firmun	2 Flaurmont – 1 Yarthmont
5	30	Birmun	2 Yarthmont – 31 Yarthmont
6	30	Sagmun	32 Yarthmont – 29 Klarmont
7	30	Sebmun	30 Klarmont – 28 Felmont
8	30	Oxmun	29 Felmont – 25 Fyrmont
9	30	Nomun	26 Fyrmont – 25 Ambyrmont
10	30	Decmun	26 Ambyrmont – 23 Sviftmont
11	30	Elfmun	24 Sviftmont – 21 Eirmont
12	30	Hinmun	22 Eirmont – 21 Kaldmont
13	12	Mitwok	22 Kaldmont – 33 Kaldmont

Weekday Number	Weekdays Name
1	Ontok
2	Totok
3	Dreitok
4	Firtok
5	Birtok
6	Sagtok

Spring		Summer		Autumn		Winter
Begin	Equinox	Begin	Solstice	Begin	Equinox	Begin	Solstice
17 Tomun	2 Firmon	20 Birmun	6 Sebmun	23 Oxmun	9 Decmun	26 Elfmun	12 Mitwok

Shadow Elf Calendar

Again this is just the normal shadow elf calendar extended to fit 372 days, so I split the Food and Cleanliness verse into 2 months, and then added an extra 12 day period which I called 'Verses' as a time when they reflect on the verses of the refuge of stone as a whole and on the past year, something to tie everything together

Month Number	Days(372/year)	Month Name	Imperial Equivalent
1	24	The Gathering	1 Nuwmont – 24 Nuwmont
2	24	The Name of the Shadow Elves	25 Nuwmont – 16 Vatermont
3	24	The Refuge of Stone	17 Vatermont – 11 Thaumont
4	24	The Shaman	12 Thaumont – 7 Flaurmont
5	24	The Crystals	8 Flaurmont – 1 Yarthmont
6	24	Birth	2 Yarthmont – 25 Yarthmont
7	24	The Wanderers	26 Yarthmont – 17 Klarmont
8	24	The Temple	18 Klarmont – 10 Felmont
9	24	Food	11 Felmont – 1 Fyrmont
10	24	Cleanliness	2 Fyrmont – 25 Fyrmont
11	24	Days	26 Fyrmont – 19 Ambyrmont
12	24	The Army	20 Ambyrmont – 11 Sviftmont
13	24	The King	12 Sviftmont – 3 Eirmont
14	24	Other Peoples	4 Eirmont – 27 Eirmont
15	24	Promised Bounty	28 Eirmont – 21 Kaldmont
16	12	The Verses	22 Kaldmont – 33 Kaldmont

Spring		Summer		Autumn		Winter
Begin	Equinox	Begin	Solstice	Begin	Equinox	Begin	Solstice
23 Name	20 Shaman	19 Birth	17 Temple	16 Days	14 King	14 Bounty	12 Verses

Holidays

and then I also adjusted the holidays to match the new calendar, some dates I based off days of the week, some based on the moon cycle, and some on the seasons

Holiday	Day	Month	Length(Days)	Nation
New Years Day	1	1-Nuwmont	1
Good Sprite Day	1	1-Nuwmont	1	Glantri
The Wintergifting	1	1-Nuwmont	1	Shaerdon
Great Rain of Fire	1	1-Nuwmont	1	City of Stars
Day of Weeping	26	1-Nuwmont	1	City of Stars
Winter Festivities	1	2-Vatermont	7	Ethengar
Feast of the Silver Purge	6	2-Vatermont	1	Minrothad
Day of the Golden Khan	7	2-Vatermont	1	Ethengar
The Rebirth	15	2-Vatermont	7	Ierendi
Gnome Caravan leaves High Forge	15	2-Vatermont	1	Karameikos
First day of Spring	15	2-Vatermont	1	Ethengar
Monsters Fair	18	2-Vatermont	1	Glantri
The Drowning	21	2-Vatermont	1	Pearl Islands
Patriarch’s Day	23	2-Vatermont	1	Darokin
Gnome Caravan arrives in Specularum	25	2-Vatermont	1	Karameikos
The Discovery	26	2-Vatermont	1	City of Stars
Festival of Lights	29	2-Vatermont	1	Sind
Beginning of shipping season	4th Nytdain	2-Vatermont	1	Thyatis
Gnome Caravan leaves Specularum	1	3-Thaumont	1	Karameikos
Landfall Day	7	3-Thaumont	1	Alphatia
Spring Break	10	3-Thaumont	7	Glantri
Fall of Aengmor	13	3-Thaumont	1	City of Stars
White Horse Ceremony	15	3-Thaumont	1	Ethengar
Arcanium	25	3-Thaumont	4	Glantri
Day of the Dead	28	3-Thaumont	1	Karameikos
Day of Irresponsibility	28	3-Thaumont	1	Sind
Opening Day	3rd Lunadain	3-Thaumont	1	Alphatia
Day of Adulthood	1	4-Flaurmont	1
New Years Day	1	4-Flaurmont	1	Sind
Parliament Day	3	4-Flaurmont	1	Glantri
Alphatian New Year	4	4-Flaurmont	1	Alphatia
Rockhome New Year	4	4-Flaurmont	1	Rockhome
Merchant Prince Day	5	4-Flaurmont	1	Minrothad
trade caravans leave Rockhome	7	4-Flaurmont	1	Rockhome
First Day of Crystals	8	4-Flaurmont	24	City of Stars
Empress Eriadna’s Birthday	13	4-Flaurmont	1	Alphatia
Day of Blessings	15	4-Flaurmont	1	Ethengar
The Firstflowering	16	4-Flaurmont	1	Shaerdon
Day of Partings	16	4-Flaurmont	1	Ethengar
Parade Day	20	4-Flaurmont	1	Glantri
Thincol’s Birthday	22	4-Flaurmont	1	Thyatis
Rockhome Marriage Arrangements	1st Soladain	4-Flaurmont	14	Rockhome
Masked Ball	3rd Soladain	4-Flaurmont	1	Darokin
Day of Magic	1	5-Yarthmont	1	Alphatia
First Day of Births	2	5-Yarthmont	24	City of Stars
Gondola Games	14	5-Yarthmont	1	Glantri
Minrothad Day	20	5-Yarthmont	1	Minrothad
First Day of Wanderers	26	5-Yarthmont	24	City of Stars
Day of Birth Blessings	1st Full Moon	5-Yarthmont	1	Ethengar
Howling Day	1st Full Moon	5-Yarthmont	1	Alphatia
Grand Patriarch's' Forum	3rd Soladain	5-Yarthmont	1	Rockhome
Freedom Day and Crown Tourney	1	6-Klarmont	1	Ierendi
The Rejection	1	6-Klarmont	1	City of Stars
The Unsheathing	22	6-Klarmont	1	Shaerdon
The Cornerstone	31	6-Klarmont	1	City of Stars
Night of the Red Moon	1st Full Moon	6-Klarmont	1	Glantri
Wedding Day	1st Soladain	6-Klarmont	1	Rockhome
Court of Golden Khan arrives at Chagon-nah	3rd Lunadain	6-Klarmont	1	Ethengar
Days of the Hoof	3rd Lunadain	6-Klarmont	7	Thyatis
Beast's Day	1	7-Felmont	1	Karameikos
The Thing	1	7-Felmont	7	Heldann
Highsummer	4	7-Felmont	14	Shaerdon
The Gathering	4	7-Felmont	1	Ethengar
Day of the Straw Men	4	7-Felmont	1	Karameikos
All's Reckless Day	13	7-Felmont	1	Minrothad
Feria de Toros	14	7-Felmont	1	Glantri
Day of Valerias	15	7-Felmont	1	Thyatis
Day of the Battle of Sardal Pass	16	7-Felmont	1	Rockhome
Feast of the Snakes	17	7-Felmont	1	Sind
Beggars Hope	25	7-Felmont	1	Glantri
2nd Return	26	7-Felmont	1	City of Stars
Doggerel Days	3rd Lunadain	7-Felmont	1	Alphatia
Night of Fire	Night before 1st New Moon	7-Felmont	1	Karameikos
Day of Heroes	1	8-Fyrmont	1	Shaerdon
Darokin Day	13	8-Fyrmont	1	Darokin
Vyonese Carnival	15	8-Fyrmont	1	Glantri
First Day of Riding	18	8-Fyrmont	1	Ethengar
The Great Horse Fair	24	8-Fyrmont	7	Ethengar
The Calming of the Seas	26	8-Fyrmont	5	Sind
Showing Day	3	9-Ambyrmont	1	Rockhome
Bask Day	6	9-Ambyrmont	1	Minrothad
1st Return	14	9-Ambyrmont	1	City of Stars
Mustering Day	20	9-Ambyrmont	1	City of Stars
Fire Night	1st Waning Crescent Moon	9-Ambyrmont	1	Glantri
Court of Golden Khan at Xantha	1	10-Sviftmont	1	Ethengar
Celebration of the Sea	2	10-Sviftmont	2	Ierendi
The Fast and the Feast	2	10-Sviftmont	12	Shaerdon
Ancestor’s Day	2	10-Sviftmont	1	Alphatia
Birth of Dandin	3	10-Sviftmont	1	Sind
Best Wishes of Krondahar	6	10-Sviftmont	1	Glantri
Ethengar New Year	6	10-Sviftmont	1	Ethengar
Vanya's Day	8	10-Sviftmont	1	Thyatis
Birthday of Tarasfir	12	10-Sviftmont	1	City of Stars
Raising of the Walls	14	10-Sviftmont	1	Glantri
Day of Counting	23	10-Sviftmont	1	Ethengar
Day of Naming and Welcoming	24	10-Sviftmont	1	Ethengar
Birthday of Telemon	24	10-Sviftmont	1	City of Stars
Duke’s Birthday	28	10-Sviftmont	1	Karameikos
Wine Festivals	2nd Lunadain	10-Sviftmont	8	Alphatia
Wine Festivals	2nd to last Lunadain	10-Sviftmont	8	Alphatia
Cretia's Day	1	11-Eirmont	1	Ethengar
Necromantia	5	11-Eirmont	1	Glantri
Glantrian Ice Games	17	11-Eirmont	2	Glantri
The Reaping	16	11-Eirmont	1	Shaerdon
Resolution Day	16	11-Eirmont	1	Sind
Outbreak Day	18	11-Eirmont	1	City of Stars
Day of Shame	25	11-Eirmont	1	City of Stars
The Night of Spirits	1st Full Moon	11-Eirmont	1	Ethengar
Harvest Day	1st Loshdain	11-Eirmont	1	Darokin
Caravan Day	3rd Lunadain	11-Eirmont	1	Rockhome
Protius’ Day	3rd Nytdain	11-Eirmont	1	Thyatis
Days of Right	31	12-Kaldmont	3	Ierendi
Animal Day	2	12-Kaldmont	1	Sind
Year’s End Feast	21	12-Kaldmont	1	City of Stars
Midwinter Festival	27	12-Kaldmont	7	Minrothad
Alexander Day	27	12-Kaldmont	1	Glantri
Day of Law	32	12-Kaldmont	1	Ethengar
Bells of Fate	33	12-Kaldmont	1	Glantri
Farewell to the Sun	33	12-Kaldmont	1
Hiding from Year’s End	33	12-Kaldmont	1	Heldann
Boldavian Procession	1st Full Moon	12-Kaldmont	1	Glantri
Footman's Games	3rd Lunadain	12-Kaldmont	7	Thyatis
Closing Day	3rd Lunadain	12-Kaldmont	1	Alphatia
Golden Khan's court at Bargda is blessed	3rd Lunadain	12-Kaldmont	1	Ethengar
Lesser Patriarch's Forum	3rd Soladain	Every Month	1	Rockhome