Princess of Argos. Zeus fell in love with Io and seduced her. To try to keep Hera from noticing he covered the world with a thick blanket of clouds. This backfired, arousing Hera's suspicions. She came down from Mount Olympus and began dispersing the clouds.
Zeus did some quick thinking and changed Io's form from being a lovely maiden. So as the clouds dispersed Hera found Zeus standing next to a white heifer. He then swore that he had never seen the cow
before, it had just sprang right out of the earth. Seeing right through this Hera complemented the cow and asked to have it as a present. As turning such a
reasonable request down would have given the whole thing away, Zeus presented her with the cow.
She sent the cow away and arranged Argus Panoptes
to watch over it. Since Argus had a hundred eyes and could have some of them sleep while others were awake he made a fine watchman. Desperate, Zeus sent Hermes to fetch Io. Disguised as a Shepard, Hermes had to employ all
his skill as a musician and story teller to gain Argus confidence and lull him to sleep. Once asleep Hermes killed Argus. As a memorial, Hera took his eyes
and set them into the tail of her favorite bird, the peacock.
While Io was now free Hera sent the mother of all gad-flys to sting the still
bovine Io. The ghost of Argus pursued her as well. This pushed her near madness, trying to escape she wandered the world. During her wanders she came across Prometheus while chained. He gave her hope. He predicted that
she would have to wander for many years. But, she would eventually be changed back into human form and would bear a child. He predicted that a
descendent of this child would be a great hero and set him free.
His predictions came true. During her wanderings many geographical features
were named after her including the Ionian Sea, and the Bosphorus (which means ford of the cow). She eventually reached the Nile where Zeus did restore her to human form. She bore Epaphus and eleven generations later her descendant Heracles would set Prometheus free.