
Not quite an ancient Greek at Eleusis.
I’ve suggested elsewhere that there’s a link between some stellar events and the scheduling of festivals in archaic Greece. What I haven’t had is a nice bit of text saying this. At least not till now. While waiting for a catalogue to come available recently I started browsing The Attic Festivals of Demeter and Their Relation to the Agricultural Year by Allaire Chandor Brumfield.
One of the festivals she talks about is Proerosia. This seems to be a sacred ploughing festival held on Pyanepsion 5 at Eleusis before the mysteries and this is firmly dated by historical inscription. There is another clue as to when it’s held as she’s found a quote from Hesychius.
καὶ ὸ δε̂μος δὲ αύτὰ προαρκτούρια καλεῖ
The key bit is προαρκτούρια, proarktouria, before Arcturus. The date she uses for the heliacal rising of Arcturus, the first appearance of Arcturus in the morning sky, is September 18. She cites a book I haven’t read for this, so I’ll have to look into it, but it seems approximately right. This is a bit of a problem because the quote doesn’t match the inscription.
The earliest match between Pyanepsion 5 in the ancient Athenian calendar to the modern calendar I can make is September 19. To get this I’ve assumed that the summer solstice was observed on June 18 as the same day as a new moon. This would surprise anyone familiar with modern astronomy, because the solstice is around June 21. However, this was not known in archaic Greece and for the days around the solstice the Sun appears to be rising over the same part of the horizon, so it is possible that it was celebrated earlier or later by a few days from year to year. If, like most years the first New Moon was considerably after June 21, then Pyanepsion 5 could be around what we would call October 21. It doesn’t seem to possible to have Arcturus rise before the Proerosia if it is held in Pyanepsion.
Another answer she considers is one put forward by Mommsen that προαρκτούρια refers to the heliacal setting of Arcturus which was, according to Columella, October 29. This would fit the data and ensure that the Proerosia was always before the Arcturus event, but as she notes it’s unusual for the setting of Arcturus to be mentioned without specifying the setting. Usually if a star is mentioned without further details if refers to its rising.
Comparing it to other texts that mention Arcturus a setting interpretation remains difficult. Hesiod in line 609 of Works and Days says “...when Orion and Sirius are come into mid-heaven, and rosy-fingered Dawn sees Arcturus, then cut off all the grape-clusters, Perses, and bring them home.” You can make a case for before the setting of Arcturus, make sure you’re ploughing’s done before he leaves because he’s the ploughman, but it smacks of excuse-making.

Bootes from the cleaned Uranographicarum.
Adding to the confusion is some queries over another inscription from Thorikos. We would expect it to be held in Pyanepsion, because this was the sacred ploughing month. However a stone from Thorikos put it in Boedromion, the month before Pyanepsion. And also possibly even in Metageitnion, the month before that. As you imagine classicists would love to get their hands on the stone but they can’t. It’s been lost. And it was only transcribed by a farmer and appears to have a lot of errors in it anyway.
On the plus side I can at least now point to another festival and say that there’s evidence that stellar calibration was used elsewhere. Yet it opens up far more questions that will need looking into.