Io

Io was a woman of Argos, but the sources do not agree on her father. Apollodorus reports three answers. Some called her a daughter of Iasus, son of Argus and Ismene. The annalist Castor and many of the tragedians made her a daughter of Inachus, while Hesiod and Acusilaus named Piren. Aeschylus follows the Inachus line in Prometheus Bound. Apollodorus adds that Io held the priesthood of Hera when Zeus seduced her, and Aeschylus's Suppliants calls her a ward of Hera's house at Argos.

Aeschylus lets Io tell her own story in Prometheus Bound. Night visions urged her to go out to the meadows of Lerna and accept the bed of Zeus. Her father sent messengers to Pytho and Dodona. At last an oracle of Loxias ordered Inachus to drive her from home, or a thunderbolt would destroy his whole race. Once she was cast out, her form and mind were changed. Horns grew on her forehead, and a gadfly drove her on. Ovid tells it differently. Jupiter spoke to her as she came back from her father's stream, and when she ran, he covered the land in cloud and caught her.

Ovid and Apollodorus both make Zeus the one who changed her. In Ovid, Juno sees the cloud, comes down, and finds a white heifer that Jupiter claims was born from the earth. She asks for it as a gift, and he cannot refuse without betraying himself. Apollodorus says Zeus turned Io into a white cow by a touch and swore he had not known her. Hera then set Argus to guard the cow, and Apollodorus says Argus tethered her to the olive tree in the grove of the Mycenaeans. Ovid's Io tries to stretch out her arms to Argus and finds she has none. She tells her father who she is by tracing her name in the dust with her hoof.

Zeus sent Hermes to take her back. Apollodorus says Hermes could not steal the cow in secret, because Hierax had given the plan away, so he killed Argus with a thrown stone. Ovid's Mercury comes as a shepherd, lulls the eyes with his pipes and the story of Syrinx, and cuts off the sleeping giant's head with a curved sword. Juno then set the dead guard's eyes on the feathers of her bird, and Ovid later says her peacocks were coloured by the death of Argus. Aeschylus says only that a sudden death took Argus, and in Suppliants the King says simply that Hermes slew him.

Hera's anger did not end with Argus. Apollodorus says she sent a gadfly, and in Ovid it is a Fury whose invisible stings drive the girl across the world. Apollodorus traces the route. Io came first to the gulf later called Ionian after her, went through Illyria and over Mount Haemus, and crossed the Thracian strait, afterwards named the Bosporus for her. She then roamed Scythia and the Cimmerian land. The Suppliants chorus sends her through Phrygia, Mysia, Lydia and the mountains of Cilicia and Pamphylia. In Prometheus Bound, Prometheus foretells a wider road, past the Scythian nomads, the Chalybes, the Caucasus and the Amazons, to the Graeae, the griffins and the Arimaspians. In Ovid, Juno recalls how Jupiter changed Io from a heifer when she rages at the nymph Callisto, set among the stars.

Every account ends in Egypt. Prometheus Bound places her healing at Canobus, at the mouth of the Nile, where Zeus restores her mind by the touch of his hand. She bears Epaphus, named from that touch, and the Suppliants tells the same story. Ovid has Jupiter swear by the Styx that Io will trouble Juno no more, and Juno allows the change back. Apollodorus adds a sequel. Hera had the Curetes make away with the child, and Io searched Syria, learned that the wife of the king of Byblus was nursing him, and found him. Back in Egypt she married Telegonus, then king of the Egyptians.

Herodotus opens his Histories with a version that leaves the gods out. Persian learned men, he says, blamed the Phoenicians for the first quarrel between Asia and Greece. Phoenician traders at Argos seized Io, daughter of Inachus, from the shore and sailed her to Egypt. Greeks later carried off Europa from Tyre and Medea from Colchis, and answered the Colchian demand for Medea by pointing to Io. The Phoenicians, Herodotus adds, denied the abduction. In their account, Io slept with the ship's captain at Argos, found herself pregnant, and sailed away with them of her own accord.

Greeks also saw Io in the gods of Egypt. Herodotus says that images of Isis show a woman with cow's horns, exactly as the Greeks picture Io. He also says that Apis, kept in a court at Memphis, is Epaphus in Greek. Apollodorus goes further. He says Io set up an image of Demeter, whom the Egyptians called Isis, and that the Egyptians gave Io the name of Isis as well. Ovid says the linen-wearing crowds of Egypt worship her as a goddess, and that Epaphus shares her temples.

Her line runs through much of Greek myth. Apollodorus traces it from Epaphus to his daughter Libya, whose sons by Poseidon were Agenor and Belus. Belus fathered Danaus and Aegyptus, and Agenor fathered Europa and Cadmus. Aeschylus's Suppliants is built on that descent: the daughters of Danaus flee to Argos and claim it as the land of their ancestress, the heifer of Zeus. In Prometheus Bound, Prometheus tells Io that a descendant of hers, the third after ten generations, will free him. Apollodorus names Heracles as the archer who shot the eagle and released Prometheus.