May 282020

The eclipse of Thales was a solar eclipse that was, according to Histories of Herodotus, accurately predicted by the Greek philosopher Thales of Miletus. If Herodotus’ account is accurate, this eclipse is the earliest recorded as being known in advance of its occurrence. Many historians believe that the predicted eclipse was the solar eclipse of 28 May 585 BCE. How exactly Thales predicted the eclipse remains uncertain; some scholars assert the eclipse was never predicted at all. Others have argued for different dates, but only the eclipse of 28 May 585 BCE matches the conditions of visibility necessary to explain the historical event. I have mentioned this eclipse before but in that post I was more interested in eclipses in general as ways of dating ancient events.

Herodotus’ Histories 1.73-74 states that a war started in the period between the Medes and the Lydians. There were two reasons for the war: the two sides had clashing interests in Anatolia, but also there was a motive of vengeance: some Scythian hunters employed by the Medes who once returned empty-handed were insulted by king Cyaxares. In revenge the hunters slaughtered one of his sons and served him to the Medes. The hunters then fled to Sardis, the capital of the Lydians. When Cyaxares asked for the Scythians to be returned to him, Alyattes refused to hand them over; in response, the Medes invaded.

Afterwards, on the refusal of Alyattes to give up his suppliants when Cyaxares sent to demand them of him, war broke out between the Lydians and the Medes, and continued for five years, with various success. In the course of it the Medes gained many victories over the Lydians, and the Lydians also gained many victories over the Medes. Among their other battles there was one night engagement. As, however, the balance had not inclined in favor of either nation, another combat took place in the sixth year, in the course of which, just as the battle was growing warm, day was on a sudden changed into night. This event had been foretold by Thales, the Milesian, who forewarned the Ionians of it, fixing for it the very year in which it actually took place. The Medes and Lydians, when they observed the change, ceased fighting, and were alike anxious to have terms of peace agreed on. [Histories 1:74]

As part of the terms of the peace agreement, Alyattes’ daughter Aryenis was married to Cyaxares’ son Astyages, and the Halys River (now known as the Kızılırmak River) was declared to be the border of the two warring nations.

An alternate hypothesis regarding the date of the battle argues that Herodotus was carelessly recounting events that he did not personally witness, and that the solar eclipse story is a misinterpretation of his text. According to this view, what happened could have been a lunar eclipse right before moonrise, at dusk. If the warriors had planned their battle activities expecting a full moon as in the previous few days, it would have been quite a shock to have dusk fall suddenly as an occluded moon rose. If this hypothesis is correct, the battle’s date would be not 585 BCE (date given by Pliny based on the date of solar eclipse), but possibly 3 September 609 BCE or 4 July 587 BCE, dates when such dusk-time lunar eclipses did occur. Generally speaking, I find this argument unconvincing. It is hard to confuse lunar and solar eclipses, and their effects on armies would have been radically different.

While doubt has been cast on the truth of the story, there are other accounts of it besides that of Herodotus. Diogenes Laërtius says that Xenophanes, who lived in the same century as Thales, was impressed with the prediction, and he also gives additional testimonies from the pre-Socratics, Democritus and Heraclitus. At the time of Thales’ purported prediction it was not yet known that eclipses were caused by the Moon coming between the Earth and the Sun, a fact that would not be discovered until over a century later by either Anaxagoras or Empedocles.

If the account is true, it has been suggested that Thales would have had to calculate the timing of any eclipse by recognizing patterns in the periodicities of eclipses. It has been postulated that Thales may have used the Saros cycle in his determination, or that he may have had some knowledge of Babylonian astronomy. However, Babylonians were far from being able to predict the local conditions of solar eclipses at that point, which makes this hypothesis highly unlikely. In fact, there is no known cycle that can be reliably used to predict an eclipse for a given location and, therefore, any accurate prediction would have been pure luck.

The eclipse peaked over the Atlantic Ocean at 37.9°N 46.2°W and the umbral path reached south-western Anatolia in the evening hours, and the Halys River is just within the error margin for delta-T provided.

On the whole, I do not think that emulating the Scythians’ dish of serving up the king’s son on a platter would be a suitable way to celebrate the day, but there are alternatives.  One is mare’s milk cheese.  The Scythians were noted for this cheese by Herodotus:

Now the Scythians blind all their slaves, because of the milk they drink; and this is how they get it: taking tubes of bone very much like flutes, they insert these into the genitalia of the mares and blow into them, some blowing while others milk. According to them, their reason for doing this is that blowing makes the mare’s veins swell and her udder drop. When done milking, they pour the milk into deep wooden buckets, and make their slaves stand around the buckets and shake the milk; they draw off what stands on the surface and value this most; what lies at the bottom is less valued. This is why the Scythians blind all prisoners whom they take: for they do not cultivate the soil, but are nomads.

Herodotus Histories 4:2

The author of the Hippocratic treatise On Generation, On the Nature of the Child and Diseases IV (which dates to the end of the 5th century BCE or the beginning of the 4th) compares the physiological process whereby a bad humor is heated and agitated in the human body to the making of mare’s cheese by the Scythians:

If the man is not purged, as the humor is stirred, there is produced an amount that is excessive. This is similar to what the Scythians make with mare’s milk. For they pour the milk into wooden bowls and shake it. As it is stirred, it foams up and separates. The fatty part, which they call butter, as it is light rises to the surface; the heavy and thick portion sinks to the bottom; they separate it and dry it. When it has become firm and dry, they call it ‘hippakē’. The whey of the milk is in the middle. Similarly in the case of man: when all the humour in his body is stirred, all the humours are separated by the principles I have mentioned: the bile rises to the top, as it is lightest; then comes the blood; third the phlegm; and the water, as it is the heaviest of the humours. (Diseases 4.51, 7.584 Littré)

Mare’s milk is fairly commonly available in central Asia (even in supermarkets) and I was offered it several times when I was in Kyrgyzstan 2 years ago.  Kyrgyz nomads are also known for making cheese from mare’s milk although the process is a bit tricky because the milk will not coagulate using cow rennet.  You can use camel rennet and maybe yak rennet also.  But there are other processes that can be employed as well, as in the above quote.  I doubt you will find mare’s milk cheese outside of central Asia, but give it a try.  It is a little reminiscent of goat’s milk cheese.  If not, maybe you can find mare’s milk.  It is normally called kumis (Russian term).