Calendars 1220-1300

Games Discussion Ars Magica
1

Hi all,

I've put together some yearly calendars for the years 1220 through to 1300. Mainly so that players know when the next moon phases/equinoxes/solstices are coming up, with regards to casting spells with durations Moon or Year. I thought that, since I already made the PDFs for them, I might as well share them.

I've also included the main religious dates that need calculation, for the three main Divine religions: Judaism, Christianity and Islam. The dates included are Yom Kippur, Easter Sunday, the start and end of Ramadan, the Laylat al-Qadr (the Night of Destiny), and the start and end of the Hajj. It should be noted that the start of months in the Islamic calendar is dependent on physical observation of the first crescent of the given moon, thus any given month can start and/or end differently than shown in different parts of the world, due to the moon rising earlier in the west, and also due to different observations in different places. This means that both Ramadan and the Hajj can be placed with a difference of up to two days in any given case, thus also moving Laylat al-Qadr accodringly. It should also be noted that, even though the night of Laylat al-Qadr is given in Realms of Power: The Infernal as being on the 27th day of Ramadan, it can actually be any odd night of the last 10 days of Ramadan, though the 27th is the most common.

Calendars 1220-1300 - English, Letter (4.63Mb ZIP file)
Calendars 1220-1300 - English, A4 (4.53Mb ZIP file)
Calendars 1220-1300 - Spanish, A4 (4.54Mb ZIP file)

You'll find three ZIP files with two PDF files in each of them. I made A4 and Letter sized calendars, each in a single ZIP file with a full-color and a printer-friendly PDF version. Me being from Spain, the weeks in the calendars start on Monday rather than Sunday. It was rather a lot of work to change that, but I thought you might find them useful anyways. There is also an additional A4-sized calendar in Spanish, also in color and printer-friendly versions.

As for the moon phases and equinoxes/solstices calculations, I made use of AstroPixels, which supposedly calculates them using the Julian calendar instead of the Gregorian calendar for dates prior to 1582. I used the Julian calendar from Time and Date for calculating which weekday corresponds to which day in the month. For Yom Kippur, I've calculated the Julian equivalent of Tishri 10th of each year at the Fourmilab website. I'll talk more extensively regarding Easter Sunday in a while. Finally, I've made use of Fourmilab to calculate the equivalent Julian dates of the Islamic calendar months.

The calculation of Easter Sunday after the First Council of Nicea (AD 325) places it in the first Sunday after the first full moon that happens on or after the spring equinox. But the Church used March 21 (the Ecclasiastical Equinox) as the date for the spring equinox, instead of the actual date of the equinox. More so, the date of full moon uses a calculated date (Paschal Full Moon) instead of the actual date of the full moon. The Paschal Full Moon, which nowadays is calculated through complex formulae, was calculated in the 13th Century from tables representing the 19 year Metonic Cicle. Easter Sundays in these calendars use the Paschal Full Moon calculation according to the Metonic Cycle and using Julian dates, which means they are different from what sould be calculated today, but use instead the system in use at the time.

Obviously, there's no guarantee whatsoever that those two resources are right for medieval dates, particularly regarding Fourmilab. But this is only a game, not serious research, so I guess it's probably ok.

Hope you find it helpful!

Edit 1: Updated the link since I extended the calendars up to AD 1240. Updated the description as well. (2016-04-15)
Edit 2: Updated the link since I upgraded the calendars to include some significant religious dates. (2016-04-18)
Edit 3: Updated the link since I extended the calendars up to AD 1300, and used a system for calculating Easter Sunday which is more appropiate for the 13th Century. Updated the description accordingly. (2020-03-24)

7 Likes
2

Seems very useful!

3

Thanks a lot. I'll be using them for my group. Any chance you could add another 5 years? We are completing 1228 in the near future ...

4

Sure, I'll add a few more years in the near future. Glad you find it useful. :slight_smile:

5

I've updated the PDF files up to year 1240. I've also included the spanish version of the calendars because I thought, why not?

Calendars 1220-1240 (6.4Mb ZIP file)

I've also updated the original post so it points to the updated ZIP file, since it also has years 1220-1230, for easier access to anybody just visiting the thread.

Edit: Edited to remove link, which is no longer valid. Please see first post for the current, valid download links. (2020-03-24)

6

Cool, thanks.

7

I've updated the calendars to include the main religious dates that need calculation, for the three main Divine religions: Judaism, Christianity and Islam.

The dates included are Yom Kippur, Easter Sunday, the start and end of Ramadan, the Laylat al-Qadr (the Night of Destiny), and the start and end of the Hajj.

It should be noted that the start of months in the Islamic calendar is dependent on physical observation of the first crescent of the given moon, thus any given month can start and/or end differently than shown in different parts of the world, due to the moon rising earlier in the west, and also due to different observations in different places. This means that both Ramadan and the Hajj can be placed with a difference of up to two days in any given case, thus also moving Laylat al-Qadr accodringly. It should also be noted that, even though the night of Laylat al-Qadr is given in Realms of Power: The Infernal as being on the 27th day of Ramadan, it can actually be any odd night of the last 10 days of Ramadan, though the 27th is the most common.

Calendars 1220-1240 (5.72Mb ZIP file)

I've updated the first post to point to the new, updated file.

Edit: Edited to remove link, which is no longer valid. Please see first post for the current, valid download links. (2020-03-24)

8

Excellent. I've made copies for each of my players. Thanks again! :slight_smile:

9

You can also got to this siteto generate Medieval Calendars

10

That's very useful! The feasts are a really nice addition, though the lack of a status bar on Firefox makes them harder to see.

11

It looks like your solstices and equinoxes are off by about a week...

though that is probably because it is Julian instead of Gregorian...

12

I have also used this site to find software to generate various calendars.

The Kalendisapp is the one I have used often.

13

I know what you mean, but I think it's because of the drift of the Julian calendar, as you pointed out. So I think the dates for the equinoxes/solstices are probably (more or less) right, and it's the calendar that was off by some days by 1220, due to the extra leap years. That's the reason why they adjusted to the Gregorian calendar after all, and when they devised it in 1582, the Julian calendar was already 13 days off to the "real" solar year. So it seems plausible that by 1220 it would be about a week off.

That said, I cannot fully vouch for the accuracy of the dates, of course. But I still think that what's wrong is the Julian dating, not the actual date. Meaning that I think the vernal equinox on 1220 (for example) would have indeed happened around March 21st on the solar year, but that the Julian calendar was misaligned to the actual, real solar year, so they "called" that day the 13th, because they were wrongly starting the year about a week late by then.

14

Hi, sorry to revive such an old topic, but since I've added to the calendars I thought it'd be cleaner to just post to the original thread instead of creating a new one.

I have extended the calendars I originally made so they cover all the years from 1220 through to 1300.

I have also changed the way I calculate the date for Easter Sunday on the calendars. I was previously placing it in the first Sunday after the first full moon that happens
on or after the spring equinox. Which is the official calculation supposedly used after the Nicean Council of AD325. But the Church actually used March 21 (the Ecclasiastical Equinox) as the date for the spring equinox, instead of the actual date of the equinox, which would have been a reasonable approximation where it not for the fact that the Julian calendar they were using back then was already off by about a week from the actual solar year.

More so, the date of the full moon they were using was a date pulled from some pre-calculated tables (the Paschal Full Moon) instead of the actual date of the full moon. The Paschal Full Moon is calculated nowadays through complex formulae that place it quite close to the actual full moon. But in the 13th Century it was calculated from tables representing the 19 year Metonic Cycle.

So I've re-calculated all the Easter Sundays in the calendars to use a Paschal Full Moon calculated from Metonic Cycle tables, which is astronomically wrong but is what people in the day would be using. So Easter Sundays are now probably more accurate to the date they were actually celebrated in the 13th Century, and thus closer to the actual date on which the it would happen for the characters.

As always, bear in mind the calendar is a Julian calendar (the one used by people at the time), and so by the 13th Century it's already off by a week or so from the actual solar year. Meaning equinoxes and solstices will appear to be off by around a week, but what is actually off is the calendar. Those are as close as I've managed to the actual dates they happened in the calendar used at the time.

I've separated the calendars into three ZIP files. Two of them are in english, one in Letter page size and the other in A4 page size, so they can be used by english-speakers from the US or elsewhere. The third one is in spanish in A4 page size; since I had already made it for my own use I thought I might as well share it. Each ZIP file has two PDF, one in full color and another one in black and white to be printer-friendly.

Without further ado, here are the calendars:

Calendars 1220-1300 - English, Letter (4.63Mb ZIP file)
Calendars 1220-1300 - English, A4 (4.53Mb ZIP file)
Calendars 1220-1300 - Spanish, A4 (4.54Mb ZIP file)

I have edited the original post to point to the current files as well as to reflect the changes in content in them.

5 Likes
15

These are great, thanks!

An interesting question that results from the fact that the calendar is off by a week: when do spells with a year duration end? I assume by the actual astronomical events and not the calendar.

2 Likes
16

For those who might need it:

https://www.staff.science.uu.nl/~gent0113/hebrew/hebrewyear_year.htm

The other online calculators I've seen get things very wrong. This is the only one I've seen that gets some pre-Gregorian dates right whose conversions I already know.

Anyway,

Ken

1 Like
17

I used this just this afternoon to find the times of the full moon for a lycanthrope. Thank you!!

Bob

1 Like
18

I would agree.

Hermetic magic does not depend on the respective local calendar. Bonisagus had a decent classical education (A&A p.11), hence knew basic astronomy and could incorporate this into the foundations of his Magic Theory.

19

I would also agree that spell Year durations would expire by the astronomical dates, not the calendar dates. Thus, the dates marked on those calendars are the astronomical dates of solstices and equinoxes (as far as I could calculate).

For example, the astronomical spring equinox for AD 1220 would take place on March 13th. People living at the time would usually consider that the equinox takes place around March 21st, but anybody with a higher education knew already that was wrong, and most of them also knew why.

As far as I know, it was a well-known fact by the 13th Century that the calendar they were using (the Julian calendar) was misaligned to the solar year. By the time they fixed it in the late 16th Century, people had been talking about the need to do so for centuries, specially in the Christian Church where it was deemed necessary to fix the misalignment so that their tables-based calculation of Easter Sunday (calculus) was accurate.

So I would say that spells Year duration would expire by the actual solstices and equinoxes (the ones I've marked on the calendar), and that magi (being highly educated) would be perfectly aware of the dates of the real astronomical solstices and equinoxes.

Also, another interesting question that comes to mind regarding the misalignment of the Julian calendar is the placement of Easter Sunday. Realms of Power: Infernal page 34 mentions in an inset that all demons in christian lands have to abandon their physical form on Holy Saturday, the day just before Easter Sunday. For AD 1220, Easter Sunday was set by the church to be March 29th, according to their Metonic Cycle tables which were wrong (among other reasons) because the Julian calendar was off. The Easter Sunday is the first sunday after the full moon on or after the spring equinox (Realms of Power: Divine page 72 inset, and also real history), but that day was actually March 22nd. Do demons abandon their physical form on March 28th or March 21st? And if it happens on March 21st (the "real" Easter Sunday), what stories can we have from that dichotomy?

20

Thanks for that link!

I just checked Tishri 10th for 4981, and it falls on September 9th, 1220, just like in my calendars. So that gives me a little more confidence in thinking the calendars I posted are probably reasonably accurate (for a game).

Thanks for sharing that. :smiley: