I’m sure we all know about Zeus’s reputation as a philanderer, and today’s myth is another one of the Horny Zeus variety. This time, the object of his affection was Io, the beautiful daughter of the river-god Inakhos. When Hera almost caught her husband in the act with the nymph, Zeus tried to cover up the affair by turning Io into a cow.
Nothing makes a person more careless than being a cuckold, and when that cuckold has powers of transformation, it results in things like that. Hera, who was obviously still suspicious, asked for the cow as a present, and Zeus couldn’t very well refuse. Actually, Io’s family were said to be devotees of Hera’s, which kind of makes this situation even worse. Anyway, Hera had Io guarded by Argos Panoptes, a giant famous as the slayer of several monsters, as well as for his hundred eyes. Zeus sent Hermes to overcome the giant, so the messenger god told Argos boring stories, eventually forcing him to close all hundred of his eyes.
Hermes then killed Argos, but Io’s troubles were not yet over. When Hera found out what had happened, she sent a gadfly to relentlessly pursue the heifer. On the advice of Prometheus, Io eventually made her way to Egypt, where she regained her human form. She gave birth to Zeus’s son Epaphus, but since he was said to have been conceived with a touch, it’s not entirely clear whether Zeus was ever actually able to have sex with Io. The nymph also married the Egyptian King Telegonus. Apparently some links have been made between Io and the Egyptian goddess Isis.
Io was the namesake for the Ionian Sea, which she presumably crossed while fleeing from Hera’s gadfly. Another place related to the myth is the Bosphorus, a strait connected the Black Sea to the Sea of Marmara. Its name means “cow-ford,” or at least that’s what the Greeks thought. Also named after Io is the first moon of Jupiter; all the first four moons of that planet, known as the Galilean moons because of their discovery by Galileo, are references to Zeus’s human partners.
Finally, I feel I should mention Blind Io, the chief of the gods in Terry Pratchett’s Discworld books.
Being the god of thunder, he has traits in common with Zeus, as well as the Norse Odin and Thor. An odd fact about his appearance is that he doesn’t have functioning eyes on his face (hence his sobriquet), but he does have many separate eyeballs that orbit his head. While the god doesn’t seem to have anything in common with the Greek Io herself, his numerous eyes are likely a reference to Argos, who was of course an integral part of Io’s story. There’s a speculation on Wikipedia that his name might also refer to the Blind Yeo, a man-made river in Somerset, England.