Io

Region/Culture: Argos and the Peloponnese, Southern Europe; the Greek world
Mythos: Greek Mythology
Primary Type/Nature: Heroes and Mortals
Mythical Attributes: A mortal Argive princess and priestess of Hera whose beauty drew the desire of Zeus and the unforgiving jealousy of his wife.
Role in Mythos: The wandering ancestress of a great line of Greek heroes, transformed into a heifer and driven across the world before she was restored and founded a dynasty in Egypt.
Relation to Humans: Io was herself a mortal woman, undone by the attention of a god and the wrath of the goddess she had served. Her endurance made her the forebear of Perseus and Heracles, so that ordinary people could trace the blood of heroes back to a girl who had been turned into a cow.

A white cow stood tethered to an olive tree in the sacred grove at Argos, and it did not rest, because the creature set to watch it never fully slept. Argus had eyes scattered across the whole of his body, a hundred of them, and he let them close only a few at a time. Some pair was always open. The cow cropped the grass under that gaze through the long afternoons and through the nights, and it could remember, dimly, being something else. It had been a girl.

Her name was Io, and she was the daughter of Inachus, the river that ran past Argos and the god who was that river. She served in the temple of Hera as one of the goddess’s own priestesses, which is the detail that makes what happened to her particularly bitter. Zeus noticed her. The stories say he came to her in dreams first, whispering that she was desired by the greatest of the gods, urging her out toward the meadows of Lerna, and when she went, he was waiting.

What came next depends on who is telling it. In one version Zeus himself turned her into a white heifer to hide the affair, and was caught in the act by his wife. In another Hera did the changing, stripping the girl of her shape as a punishment. Either way the outcome was the same. Hera, suspicious of a cow that had appeared from nowhere, asked her husband for it as a gift, and Zeus, unable to refuse without confessing, handed his lover over in the body of an animal. Hera tethered the heifer and set Argus Panoptes to guard her, and there was no better jailer in the world than a giant who could sleep and see at the same time.

Zeus sent Hermes to free her. Hermes came down disguised, and rather than fight the hundred-eyed watchman he bored him. He played long slow tunes on a reed pipe and told a story about how the pipe had come to be, the tale of the nymph Syrinx who turned herself into marsh reeds to escape the god Pan. It went on. One by one the hundred eyes drooped and closed, until the last of them had shut, and Hermes drew his blade and struck off the sleeping head. Hera took the eyes of her dead servant and set them into the tail of the peacock, where they still stare out in rings of blue and gold. She had lost her guard. She was not finished with Io.

She sent a gadfly. It was a small thing to carry so much malice, but it fastened on the heifer and stung without pause, and the pain of it drove Io out of the grove and across the earth in a blind panic. She ran through Greece and up into the mountains, swam a strait so broad that afterward it kept her crossing in its name, the Bosphorus, the ford of the ox. She crossed the water that later people would call the Ionian Sea after her. There was no rest anywhere in it. The insect burrowed at her flank, the sun beat down on her white hide, her hooves split on stone, and still she ran, because to stop was to feel the sting bite deeper.

Somewhere in the far mountains of the Caucasus she came upon Prometheus, chained to the rock for his own crime against Zeus, an eagle at his liver. He knew her, and he knew her future. He named the long road still ahead of her, the wild peoples and the monsters she would pass, and he named the reward waiting at the end of it. From her body would come a line of descendants, and in the thirteenth generation one of them would break his chains and set him free. That descendant was Heracles. The tormented girl was carrying, without knowing it, the ancestor of the strongest hero the Greeks ever imagined.

The road ended in Egypt. There Zeus came to her a final time, and with a touch of his hand, no violence in it now, he gave her back her own shape. She bore him a son and called him Epaphus, from that touch. The Greeks who told the story said the Egyptians honored her afterward as the goddess Isis, and her son as the bull Apis, so that the wandering cow became a queen and then a god in a foreign country. Her children’s children came back to Greece. Through Epaphus ran the blood of Danaus and his fifty daughters, of Perseus, of Heracles himself. A whole shining pedigree began with a girl who had been turned into livestock and chased halfway around the world by a fly.

She had no power of her own. That is the hard center of the story. Io works no magic, wins no battle, outwits no one; everything is done to her, by a god who wanted her and a goddess who could not forgive her for being wanted. Her single strength is that she does not die. She endures the gadfly, the ocean, the endless running, the loss of her own face, and she comes out the other side still herself, still able to hold a child. The gods around her are enormous and careless with their cruelty. Io simply lasts, and in lasting she outproduces every one of them, seeding the earth with heroes whose names would outshine her own.

Frequently Asked Questions

Who was Io in Greek mythology?

Io was a mortal princess of Argos and a priestess of the goddess Hera. She was loved by Zeus and, to hide or punish the affair, was transformed into a white heifer. After long suffering she was restored to human form in Egypt and became the ancestress of a major line of Greek heroes, including Perseus and Heracles.

Why was Io turned into a cow?

Io was turned into a white cow because Zeus desired her and wanted to conceal the affair from his wife, Hera. In some versions Zeus himself performed the transformation and was caught; in others Hera changed Io as a punishment. Either way, Hera then claimed the heifer and set the hundred-eyed giant Argus to guard her.

Who was Argus and what happened to him?

Argus Panoptes was a giant covered in a hundred eyes, set by Hera to watch over Io in her cow form because he could keep some eyes open even while sleeping. Zeus sent Hermes, who lulled Argus to sleep with music and a long story before killing him. Hera honored her dead servant by placing his hundred eyes on the tail of the peacock.

Where did Io’s wanderings end?

Io’s wanderings ended in Egypt, after a gadfly sent by Hera drove her in agony across Greece, Asia, and the sea. There Zeus restored her to human form with a gentle touch, and she gave birth to his son Epaphus. The Greeks identified her in Egypt with the goddess Isis and her son with the sacred bull Apis.

Who were Io’s descendants?

Io was the ancestress of one of the greatest lineages in Greek myth. Through her son Epaphus came Danaus and his fifty daughters, and later the heroes Perseus and Heracles. The prophet Prometheus foretold that Io’s descendant in the thirteenth generation, Heracles, would one day free him from his chains.