#my intercalary month is starting at the next new moon and it's going to be a welcome break

[thegrapeandthefig]

The three festivals which I've placed in the Thasian month of Thargelion (which is out of sync with the Athenian calendar for now, things will line up again next month.)

The Great Herakleia and the Choreia are both atttested in the festival list provided by inscription SEG xix 415 as festivals for which legal business was not permitted at the end of the 4th century on the island. Herakles was the city's patron deity alongside Dionysus, so it is not surprising for their respective festivals to be considered as important.

I celebrate the Herakleia on the 4-5th. Historically, Herakles received the sacrifice of an ox was worshipped under the epithet of Kallinikos (fair victor). I have kept the epithet and offer beef-based foods.

The Thargelia is an personal addition based on the fact that the month of Thargelion is attested for Thasos. There is solid ground to assume that the Thargelia was celebrated on the island, mainly from the fact that this is one of the most widespread festivals in the Greek world, including in Thasos' mother city, Paros. It is not an exact copy of the Athenian version, but I have kept the main elements. I celebrate it on the 6th-7th for Artemis and Apollo, with an emphasis on the Delian (Delia, Delos) epithets, due to Thasos' heritage of cycladic influence. I have kept the staple offering of panspermia, which I make using figs, seasonal fruits, milk and oat flakes.

And the final festival for the month is the Choreia for Dionysus, which is not well known and attested nowhere outside of Thasos, except for Dionysus' epithet Choreios which Plutarch claims is from the island of Paros, Thasos' mother city. The festival is assumed to have involved dancing, singing or theatrical contests, but we do not have enough information about it to know. I celebrate it on the 12th-15th of the month and typically offer beef and fennel, as well as wine. This year I served it in a samoon bread because I felt like it (it pairs wonderfully).

Keep in mind that my personal practice is both very speculative and locally-focused. I share details of my practice only for the sake of sharing the methodology behind what I do and doesn't mean that my way of doing things is the only possible way.

[troutfur]

Lunar Calendar for WC draft #1

Been toying with calendar math because I was making a timelline for my current writing project and I've come up with an idea for a potential calendar the cats could use. All this is probably too complicated math for the cats and the timespan it'd take to notice these cycles makes it very unlikely cats with natural lifespans would even be able to notice them, BUT! At the very least it helps me keep better track of time, particularly when dealing with stories taking place over a period of like a year.

So, without further ado!

[Image ID: A 5 column, 12 row table with 56 entries that go on a pattern of New Moon symbol to First Quarter symbol to Full Moon symbol to Last Quarter symbol. The symbols have a number 1-14 next to them showing whether it's the first, second, etc of that kind of symbol on the table. The cells of the table are color coded, the first 13 entries are green, the next 13 yellow, the next 13 orange, the next 13 blue, and the last 4 purple.]

To explain it a little bit, this table shows the weeks of the year, assuming a regular lunar month of 28 days and thus 4 regular lunar weeks of 7 days, each starting with a different lunar phase, be it New Moon, First Quarter, Full Moon, or Last Quarter. The color coding corresponds to the seasons: Greenleaf in green, Newleaf in yellow, Leaf-fall in orange, Leafbare in blue, and Intercalary (I'll explain later) in purple.

28 days in a lunar month times 13 lunar months equals 364 days in a lunar year, with an equinox or solstice marking the transition from season to season happening regularly in intervals of 13 lunar weeks. The start date is set at the first New Moon of Newleaf.

As far as I'm concerned, that's good enough. We are already assuming regularity for the lunar month when the length of a lunation is in reality ~28.5 days. We can just say the year in the WC world is 364 days exactly instead of ~365.25 days. But in case you want to add a complication, I also added to the table the intercalary month/season.

Because of the discrepancy between the 364 day lunar year and the roughly 365.25 day solar year, once every 12 years this calendar falls out of sync with the equinoxes and solstices by about 27 days. To fix this, your cats could add a 14th month every 12th year to bring it back into alignment. That overcorrects for a year but I honestly don't care enough to keep doing the math to figure out in how many centuries the 1 day error accumulates and the cats will have to skip the leap month. If you want the math to be a little more perfect, you can just say the year in the WC world is not ~365.25 days long but rather exactly 365.33333... days long.

[datasoong47]

One of my lesser special interests is calendars.  There’s something about different calendar systems that I find fascinating. I think it’s the way that they’re a combination of natural phenomena (the day and year both being natural cycles, and the moon for lunar calendars) and artificial divisions, especially divisions such as the week, which have no physical basis.  Why is today Thursday?  Because yesterday was Wednesday.  And yesterday was Wednesday because the day before that was Tuesday, and so on back to whoever it was that first started the week. It’s kinda cool to think about how we’ve been faithfully counting out seven days at a time for over 2,000 years

But of all the calendar systems I’ve read about, the pre-Julian Roman calendar is my favorite, because it’s such a wild mess

A “common” year had 12 months, most of them 29 days, with four (March, May, July, and October) having 31 days, and one, February, with 28, for a total of 355 days. In a leap year, an additional month, known as mes intercalarius (intercalarius being derived from the verb intercalo “I postpone”) was added after February. As the year originally began with March, that meant the extra month was added to the end of the year, delaying the start of the next year.  This month was also known as Mercedonius.  This additional month was 27 days long.  However, in years in which it was added, February was shortened by 4 or 5 days, so that it ended instead on the 23rd or 24th of February, and the year was 377 or 378 days long. There were two festivals held on the 24th and 26th of February in common years which were in leap years were moved to the 23rd and 25th of Mercedonius

It is thought that leap years alternated between 377 and 378 days, though actual records are unavailable to test that. The Roman priesthood was responsible for determining in which years the extra month would be added, but they were not required to announce it until the Ides of February, that is, the 13th of February. This worked out all right when Rome was a single city surrounded by villages, but once Rome began to expand into a great power, this became quite inconvenient. News of whether the extra month would be added could take weeks to reach remote provinces - a major inconvenience since you wouldn’t even know what day it was! Imagine being some poor bureaucrat who has to go back and correct a bunch of dates because you found out that it had been a leap year. This was especially a hassle for planning military campaigns, and so, during major wars, leap years would be skipped. And then there are said to have been times when the priests would add the extra month because they were friends with the Consuls, whose terms lasted one year - adding an extra month would extend their term a few weeks

Now, this is such a wild mess that I just love it. It’s not a normal solar calendar, which typically adds a single leap day. Adding a whole month is more typical of lunar calendars. And yet, their months were not at all aligned with the moon. The 355-day length of the “common” year is similar to a common year in a lunar calendar. 12 lunar months works out to a little over 354 days. And some Roman writers claimed that February had originally been 27 days, but an extra day was added at some point. This does seem plausible, since the calendar itself was probably originally based on a lunar calendar, so 354 days in a common year would make sense. Also, the fact that the intercalary month was 27 days fits that theory - the extra month in many lunar calendars is simply a repeat of one of the regular months, so in this case, it’s plausible to assume that it was originally simply a repeat of February, and thus, the same length. The odd month lengths are said to have been a result of the belief that odd numbers were lucky - which is also said to have been why February was subsequently lengthened to 28 days, making the year an odd number of days

So, the likely origin of the calendar was a normal lunar calendar, with months of 29 or 30 days, and a periodic insertion of an extra month to keep up with the solar year. Someone at some point moved days from some of the 30-day months to others, to make a mix of 29- and 31-day months. But why was February left at 28, or 27 if you go with the “a day was added later” theory? Why not 29 days, with only 3 months being 31 days?

That change would’ve caused the calendar to drift out of sync with the moon, especially with the intercalary month being only 27 days

There is a rather interesting mathematical observation to be made with this system. Assume that the intercalary month was added every other year. And further assume that the leap years did, indeed, alternate between 377 and 378 days. So, over a four-year period you’d have the following pattern:

355 days

377 days

355 days

378 days

Now, average these out, and you get 366.25 days. About one day longer than the actual solar year! This is further circumstantial evidence for the “February was originally 27 days” theory.  Subtract one day from February, but assume the same rules otherwise, including the “subtract 4 or 5 days from February” rule, and you’d get an average length of 365.25 days. So, it seems reasonable to me that the rule of dropping days from February in leap years originated when February had 27 days, and was done to create a simple leap year rule - add the intercalary month every other year, and alternate between dropping 4 or 5 days from February in those years (though why the intercalary month wasn’t shortened instead is a whole other question), to make an average year of 365.25 days. However, once February had an extra day added to it, that rule no longer worked, as the year would drift out of phase with the seasons, and fairly quickly, too. So, the priests would sometimes have to have two common years in a row

Julius Caesar later came along and radically simplified this by dropping the intercalary month entirely, and adding one or two days to each of the 29-day months, to make some 30 days and others 31. For whatever reason, he left February at 28 days in non-leap years. The leap day, interestingly enough, was actually simply a doubling of February 24, that day apparently chosen because it was often the last day of February in leap years in the old calendar. And because the calendar had drifted by several months from the seasons, the year 46 BC, the last one before his new calendar took effect, was given three leap months, for a total of 445 days. This changed the calendar from an unholy lunar/solar hybrid to a fairly boring solar calendar

It’s interesting to me that he made a large-scale reform instead of, say, simply changing the rules for leap years. For example, one could imagine instead simply requiring that the addition of the extra month be proclaimed much earlier, with enough advance notice for the news to get out to even the most distant province. Another solution would’ve been to simply create a formal set of rules for adding the extra months. There are several possible ways to do this, but all would be based on a 24-year cycle, in which 13 years are “common” years (355 days), 7 are “short leap” years (377 days) and 4 are “long leap” years (378 days).  One such rule was actually suggested by a Roman writer well after Caesar’s reform - you’d have four cycles with the 355/377/355/378 rule. Then the fifth cycle would have both leap years be the “short” kind, that is, 355/377/355/377, and the sixth cycle would have the last year be common, thus 355/377/355/355

Or, of course, one could imagine simply going back to the 27-day February, or dropping 2 days from the intercalary month, and either way, a simple 4-year cycle would be possible. It’s very probable that part of the reason for simply completely revising the calendar was his familiarity with the Egyptian solar calendar. Having learned of a calendar that doesn’t bother with leap months and instead is simply directly linked to the solar calendar, he presumably decided “Hey, that’s a pretty rad idea, we should do that here in Rome too!”

Also, perhaps he simply didn’t trust the priests whose job it was to regulate the calendar to get it right - which would clearly be justified by the fact that they misinterpreted his leap year rule. Where he wrote that the leap year should be after every third year (that is, three common years followed by a leap year) they misinterpreted that as the leap year should be every third year, meaning that they added too many leap years. August later had to fix that by skipping several leap years to bring the calendar back into line, then fixing it at the every-fourth-year rule. So, if they screwed up such a simple rule, then presumably any more complex rule would’ve been screwed up even worse

Still, I like to imagine an alternate timeline where Caesar instead simply reformed the leap year rule. Presumably later an equivalent of the Gregorian reform would come around, which would work by setting another rule for making certain would-be 378-day years 377 instead. It would be particularly interesting in how it would intersect with lunar-based calendars such as the Jewish calendar, or the calculation of the Christian Easter, since both the Roman calendar and a lunar calendar keep only roughly in line with the solar calendar, and the rules for adding an extra month are so different. They both fluctuate around the solar year, but nowhere near in sync with each other, so sometimes the Roman calendar would be “early” relative to the solar year while the Jewish calendar is “late”, and sometimes the other way around, so dates of Jewish festivals on the Roman calendar would fall in an even bigger range of dates than with the Julian or Gregorian calendars