Introduction
Io is a mortal priestess of Hera at Argos, pursued by Zeus and, in an attempt to conceal the affair, transformed into a white cow, either by Zeus himself for concealment or by Hera in punishment, depending on the version. Her subsequent, tormented wanderings across much of the known world are among the more extended journey-narratives in Greek myth.
This figure marks the point where the genealogy of the gods gives way to the genealogy of heroes. A fuller account of their adventures belongs to a separate treatment of the Greek Heroic Cycle; this article covers their divine parentage and place in that transition.
Family
- Husband: Zeus
- Son: Epaphus
Transformation and the hundred-eyed guardian
Hera, suspecting the deception, asked for the cow as a gift, and Zeus, unable to refuse without revealing his guilt, complied. Hera set the hundred-eyed giant Argus Panoptes to guard her, since with so many eyes he could always keep some open even while others slept. Zeus sent Hermes, who lulled all of Argus's eyes to sleep with music and a story, then killed him; Hera, in tribute, placed his hundred eyes on the tail of the peacock, her sacred bird.
The gadfly and the wanderings
Still not satisfied, Hera sent a maddening gadfly to sting the cow-form Io relentlessly, driving her in a long, painful flight across much of the Mediterranean and beyond, a journey that later gave several bodies of water, including the Ionian Sea and the Bosporus ("ox-ford"), their names in Greek etymological tradition. Io eventually reached Egypt, where Zeus restored her to human form, and she bore him a son, Epaphus.