Calendar manipulation in Ancient Greece
This really isn’t a topic I’m thrilled to tackle, but since the Theogamia there has been so much talk about calendar discrepancies that it looks like the right time to bring this up. Don’t expect this to be eloquent, I’m writing this while absolutely knackered.
I’m not going to focus too much on the problem of modern calendar reconstructions, what I’ll be going into here is the historical evidence we have about how awfully inconsistent the ancient Athenian calendar could be, either by nature or by human intervention over time.
The problem of the new moon
In theory, the Athenian calendar and other Greek calendars are lunar and each month begins on the new moon. Sacha Stern, in Calendars in Antiquity, tells us that the writer Geminus (1st c. BCE), states that the Greek month began when the new moon crescent was first sighted but Geminus also states that the new moon can sometimes be sighted on the 1st of the month, but sometimes not until the 3rd. This statement is interesting, because it implies that, should the moon not be visible (clouds), there was a mathematical basis to the calculation of the months that still made the month begin regardless of what the sky looked like.
There comes also the problem of conjunction (aka when the moon in orbit passes between the sun and the earth, making the moon invisible). The traditional ancient assumption is that the day of conjunction is the last day of the month. However, the interval between the day of conjunction and of the new moon is usually around two days; so if the month began when the new moon was first sighted, conjunction should have been typically on the penultimate day of the previous month.
Those difficulties, along the fact that other authors, such as Aratus give conflicting information leads Stern to say this:
Modern scholars have generally accepted Geminus’ statements that the Greek month began at first visibility of the new moon. However, it is clear on Geminus’ own evidence, as well as on the evidence of the other passages just mentioned, that this rule was not strictly followed, and indeed, quite possibly, that it did not constitute a rule. Moreover, we do not know of any procedure that may have been used, and indeed that would have been necessary, for such a rule to be enforced. There is no evidence, for example, in the whole of Graeco-Roman literature of anyone sighting the new moon.
And this leads us to the rather uncomfortable idea that, in practice, a lot of the calendars simply might not have been as well aligned with astronomical moon phases in the way we conceptualize it today.
Francis M. Dunn, in an article titled Tampering with the Calendar, lists passages from ancient Greek sources that seem to corroborate this idea:
Thucydides 2.28 in a passing mention of a solar eclipse […] distinguishes the astronomical "new moon" or conjunction, at which eclipses must occur, from the conventional "new moon" or noumenia, which followed the first visible crescent. The historian, in other words, is aware that there is an astronomical "new moon" or conjunction which is different from the first day of the civic month.
Man-made adjustments
Because calendars impacted the religious, civic and political lives of each city-states, it wasn’t uncommon for city-states to make adjustments to them.
The type of modification we’re most used to is the addition of intercalary days or month that aim to realign the calendar with astronomical reality. But we have evidence that this isn’t the only motivation.
- In the 430's (SEG XXXVI 12), 420's (SEG XL 12) or 410's (SEG XLII 17), in connection with offerings at Eleusis, the demos instructed the archon to add a second Hekatombaion.
- In 228/7 a second Hekatombaion was added to the civic calendar.
- Between 294 and 288, in connection with a tour by artists of Dionysus during Lenaion, four cities in Euboea made provision for the archons to add months as necessary.
- At the end of the fourth century, probably in 307/6, two days were apparently added near the end of Gamelion.
- In 271/0 four days were added in the first decade of Elaphebolion.
As we can see, additions and subtractions of one or several days, if not sometimes months, could happen. They were often added either at the beginning of a month or at the end of a month, which makes it easier to imagine that it could be done to readjust the calendar to the moon, but in the cases where it was linked to a festival, it was clearly done to schedule said festival:
”Of the three cases of intercalary months, two are explicitly related to religious festivals (the dedication of first fruits at Eleusis, IG I3 78; and dramatic festivals in Euboea, IG xii.9 207”
“The evidence therefore supports an assumption that most adjustments were part of the normal operation of the civic calendar - ensuring that the calendar was roughly in phase with sun and moon, and ensuring that festivals would take place at a necessary or convenient time.”
An insoluble debate
The problem of ancient Greek calendars as a whole has been a point of contention among scholars for so long, for the simple reason that it makes dating anything difficult. The most notable example is the one around the differences between the Athenian calendar and the Spartan one when it comes to dating something like the battle of Marathon. Plutarch tells us it was on the 6th of Boedromion, but Herodotus tells us it was during the full moon (and therefore later, if the calendars matched the lunar cycle). This is where the issue of inter-city calendar alignment emerges, since each city-state functioned in their own independent ways, they could resort to calendar adjustments at any time they wanted and further misaligning themselves with one another.
But scholars don’t necessarily agree! Some, like Pritchett believed that the calendars were irregular no matter what, while others like Meritt believed they were regular, and that the evidence of irregularity was due to exceptional circumstances. The problem at this point is that it is much harder to prove regularity than the opposite.
So where does it leave us?
The reconstructed calendars we use today as modern worshippers are all based on some form of regularity, but we need to remember that none of them are a direct continuation of the ancient calendars. For the most part, they are based on the metonic cycle and on the other luni-solar calendars in use today by various faiths and cultures around the world. In fact, a lot of the reconstructions of Athenian calendars are using the same mathematical model as the Hebrew calendar. And that, in a nutshell, explains why different reconstruction have different results when it comes to placing specific days and festivals. So it really comes down to personal choice. Choosing a calendar that is more “popular” might be more appealing to you for particular reasons, while others might choose their calendar based on entirely different criteria. I guess the point I’m trying to get to is that, there won’t be a “standard” calendar without some kind of wide decision to stick to a precise model, and as long as there is no religious authority, the calendars will remain ever so slightly different, because they never really were regular in the way that we understand our solar Gregorian calendar to be.