Among Zeus's offspring were great heroes such as Perseus, Castor and Polydeuces, the great Heracles. Some were founders of cities or countries, like Epaphus, who founded Memphis; Arcas, who became king of Arcadia; Lacedaemon, the king of Lacedaemon and founder of Sparta. One was the wisest law-giver of his age, the first Minos. Another was a fabulous beauty, the famous Helen of Troy. And one was a monster of depravity: Tantalus, who served up his son Pelops as food to the gods. As a general rule Zeus's mortal children were distinguished for one reason or another.
On occasion their mothers were notable for something besides merely attracting Zeus with their beauty. Leda, for example, after being visited by Zeus in the form of a swan, gave birth to an egg from which came Helen and Clytemnestra, and Castor and Polydeuces. But since Leda's husband Tyndarus also made love to her shortly after Zeus, the exact paternity of these quadruplets was subject to question.
Poor Io was famous for her long persecution at the hands of Hera. Zeus fell in love with Io and seduced her under a thick blanket of cloud to keep Hera from learning of it. But Hera was no fool; she flew down from Olympus, dispersed the cloud, and found Zeus standing by a white heifer, who of course was Io. Hera calmly asked Zeus if she could have this animal, and Zeus gave it to her, reluctant to go into an explanation. But Hera knew it was Io, so she put her under guard. The watchman Argus with a hundred eyes was put in charge. Eventually Zeus sent his son Hermes to deliver lo from Argus, which was very difficult because Argus never slept. In disguise Hermes managed to put Argus to sleep with stories and flute-playing, and then Hermes killed him. As a memorial to Argus, Hera set his eyes in the tail of her pet bird, the peacock. But Hera was furious and sent a gadfly to chase Io over the earth. Still in the form of a heifer, Io ran madly from country to country, tormented by the stinging insect. At one point she came across Prometheus chained to his rock in the Caucasus, and the two victims of divine injustice discussed her plight. Prometheus pointed out that her sufferings were far from over, but that after long journeying she would reach the Nile, be changed back into human shape, give birth to Epaphus, the son of Zeus, and receive many honors. And from her descendants would come Heracles, the man who would set Prometheus free.
