I have been researching Istros drachms, because I find the symbolism interesting. Studying possible explanations for the inverted pair of heads, I ran across a fascinating article written by two astronomers at Cambridge, who propose these coins may be a stylized depiction of an eclipse witnessed in ancient times. While there is no real proof
, it is sure an interesting read--click to read the pdf.
Ancient Greek texts describe Helios as "piercingly gazing with his eyes (1)" or "flashing eyes, which shot out rays of golden light ". Coins of Rhodes depicting Helios do have highly emphasized eyes, and the eyes on Istros coins do appear to have a similar emphasis.
Here are just a few depictions of Helios compared to the wide-eyed Istros coins.
What I found fascinating about this article is how the astronomers tried to visualize the impact of the 431 BC eclipse to the people at the time. To the ancients, the sun was not a star as we understand it today; it was literally the physical manifestation of gods who inhabited the sky, including Helios. Therefore, it's quite reasonable to propose the 431 BC eclipse would be interpreted
as an act of the sun god; here is how this eclipse would have appeared to the viewer:Notice how the "horns" of the eclipse invert from beginning to end? If the sun was Helios, how might an ancient interpret this event?
Here the astronomers describe how the event may have been seen by the viewer:
Another compelling piece of evidence are several eclipse tracks near Istros close to the time these coins were minted:
I hope you enjoyed the article! (1)Homeric Hymn 31 to Helius (trans. Evelyn-White) (Greek epic C7th - 4th B.C.)
(2)Apollonius Rhodius, Argonautica 4. 726 ff (trans. Rieu) (Greek epic C3rd B.C.) :