Olympic Astronomy

Stadium Entrance, Olympia.

This came about from a conversation with Nicholas Kollerstrom at the National Astronomy Meeting. Having worked on how Delphi’s oracle was timed, he suggested that I look into the Olympics. This seemed like it should be comparatively easy, not because you only have to explain one year in four, but because he more or less gave me the answer during the talk. The Olympics, he said, could be tied to the Venus cycle.

I should point out that if I had read the Da Vinci Code then I would have known this would be a dead end.

Venus is a peculiar planet to observe. The ratio of the orbits of Venus and Earth is extremely close to 8:5. This means that if you observe Venus one night and then come back at the same time eight years later then you’ll see Venus in almost exactly the same place in the sky. This has been used by cultures as diverse as the Mayans and the Babylonians (see Anthony Aveni’s Conversing with the Planets). The Greeks got a lot of the astronomical knowledge from the Babylonians, so it seemed plausible.

It became more interesting when I looked at the night skies over Olympia around the time of the ancient Olympics. The first recorded games are in 776 BC. I don’t know the exact time of year they were held, because the evidence is confused and contradictory, but August-ish would seem to be a fair approximation. This is exciting because at this time Venus is visible just setting after sunset. This is the sort of thing that Hesiod, who wrote a book which included astronomical tips, was looking for. So it all seemed to match what I knew of Greek astronomy. Of course this would only happen every eight years, and the Olympics happened every four years. Unless you were Greek. The Greeks thought they happened every five years.

They called the Olympics a Penteric festival, and thought the cycle worked something like this.
Year One: Olympic Games
Year Two: Isthmian and Nemean Games
Year Three: Delphic Games
Year Four: Isthmian and Nemean Games
Year Five: Olympic Games
The counting was inclusive. Five is a terribly exciting number if you’re interested in Venus because of this 8:5 ratio I mentioned. Venus makes five different appearances in the morning sky, and five different appearances in the evening sky during this eight year cycle.

Even more excitingly later authors like Geminus record there was an eight year cycle used to determine Olympic dates in later times. It was a cycle of ninety-nine lunar months, with periods of forty-nine and fifty months between the games. Then the earlier appearances of Venus are roughly ten months earlier, and the earliest heralds were said to leave Olympia to announce 10 months of sacred training time before the games. In the archaic period Venus was thought to be a twin of two heralds Eos, herald of the dawn, and Phosphoros, herald of the evening. When you add in that the Delphic Games were originally held on an eight year cycle then you can become slightly blinded to the problems.

And there are problems.

I’m certainly not the first to look into this Venus correlation. Up till the 1920s there were a few people looking at it and you can find people blithely stating that the Olympics were tied to the cycle of Venus. But when you actually try and find a reference that they cite for this you I couldn’t find any reference to ancient material.

Then there’s the problem that the Olympics are every four years rather than eight. What happens in the other half of the cycle? Venus is visible in the morning sky, but it’s not doing anything spectacular when it happens. You’d struggle to use it to calibrate a calendar like you could for the 776 appearance. But the biggest problem happens when you think what Venus was thought to be.

The Venus cycle in Babylon was a fertility festival. It was celebrated as Ishtar which could be transposed into Greek mythology as not just as Aphrodite, but also Artemis and Athena. In any event it seems to be a celebration of feminine fertility. So how did the Greeks celebrate this at the Olympics?

They got a couple of blokes to strip naked and try and punch their opponent unconscious.

Two blokes fighting on a vase. Photo from Pankration Research Institute.

There were other events too, but the ancient Olympics were a masculine event. Women were barred from the sanctuary, so it there’s a real problem if you want to hold on to the idea that the Olympics were a Hellenised form of the Venus festivals of Babylon. There’s correlation certainly, but not causation. It seems more likely that the Olympics were held every four years because the Greeks were happy with that for other reasons and Venus had nothing to do with it. It’s not as if four is a difficult number to count to, particularly if you have friends across the Greek world helping.

But this is interesting because without the historical evidence from Babylon we wouldn’t know what the Venus festival was about and could easily jump to the wrong conclusion. What you usually find in the archaeological record are correlations. Making the leap to causations is tricky. Without historical evidence it might be that there is little we can say about prehistoric astronomies.

So if I do seem convincing about prehistoric astronomy sometimes, bear in mind I could be dead wrong.