Source Verification: Io
Every claim below is either what a named ancient source attests, in its own line or section, or a point where the sources themselves disagree.
What the Sources Attest
Who is Io in Greek mythology?
Io is a princess of Argos whom Zeus loved. Apollodorus says she was a priestess of Hera, and he records three fathers for her: Iasus, the river Inachus, or Piren. Changed into a white cow, she was guarded by Argus until Hermes killed him. Hera then drove her across Europe and Asia with a gadfly. In Egypt she recovered her form and bore Epaphus, ancestor of Danaus, Aegyptus and the house of Agenor.
Source: Apollodorus, Library 2.1.3; Apollodorus, Library 2.1.4
Why did Zeus turn Io into a cow?
To hide the affair from Hera. In Ovid, Juno sees an unnatural cloud over the fields and comes down to look, and Jupiter changes Io into a white heifer before she arrives. He claims the animal was born from the earth. Apollodorus says Zeus changed her by a touch once Hera had caught him, and swore he had not known her. Not every source blames Zeus. In Aeschylus's Suppliants, the King says the goddess of Argos herself turned the woman into a cow.
Source: Ovid, Metamorphoses 1.583-649; Aeschylus, Suppliants 291-315
Why did Hera torment Io with a gadfly?
The sources present it as Hera's anger at Zeus's love for Io. In Apollodorus, the gadfly comes straight after Hermes kills Argus on Zeus's orders. Ovid makes the torment Juno's revenge once Argus is dead: she plants a Fury's invisible stings in the girl and drives her across the world. In Prometheus Bound, Prometheus tells the chorus that Io's sufferings come at Hera's hand. He also blames Zeus, whose desire for a mortal girl has imposed these wanderings on her.
Source: Aeschylus, Prometheus Bound 700-740
How did Io return to her human form?
Zeus restored her in Egypt. In Prometheus Bound, Prometheus foretells that at Canobus, by the mouth of the Nile, Zeus will bring her back to her senses with the mere touch of his hand, and she will bear Epaphus. Ovid gives a fuller scene. Io collapses by the Nile and bellows to the stars, and Jupiter swears by the Styx that she will trouble Juno no more. Juno relents, and the heifer's hair, horns and hooves give way to a woman's body.
Source: Aeschylus, Prometheus Bound 846-850; Ovid, Metamorphoses 1.712-746
Who were the descendants of Io in the myths?
Her son Epaphus ruled Egypt and fathered Libya, Apollodorus says. Libya bore Agenor and Belus to Poseidon. Belus fathered the rival brothers Danaus and Aegyptus, whose fifty daughters and fifty sons carry the story of Aeschylus's Suppliants. Agenor went to Phoenicia and fathered Europa and Cadmus. Prometheus Bound adds that one of the Danaids would found a royal line in Argos, from which the bowman who frees Prometheus would come.
Source: Apollodorus, Library 2.1.4; Aeschylus, Prometheus Bound 846-875
Where Accounts Differ
- who Io's father was
- whether Zeus or Hera turned Io into a cow
- how Argus died
- whether a gadfly or a Fury drove Io
- the route of Io's wanderings
- whether Io was abducted or left willingly
- Io's father differs by source. Apollodorus (Library 2.1.3) records Iasus, son of Argus and Ismene, then says the annalist Castor and many tragedians made her a daughter of Inachus, and that Hesiod and Acusilaus named Piren. Aeschylus (Prometheus Bound 663, 705), Ovid (Metamorphoses 1.583-649) and Herodotus (Histories 1.1) all make her the daughter of Inachus. The Hesiodic account is known here only through Apollodorus.
- Who changed Io into a cow differs. Apollodorus (Library 2.1.3) and Ovid (Metamorphoses 1.583-649) make it Zeus, hiding her from Hera. In Aeschylus's Suppliants (291-315), the King says the goddess of Argos transformed her. In Prometheus Bound (640-685), Io says only that her form and mind were distorted after Inachus drove her out on the oracle's command.
- How Argus died differs. Apollodorus (Library 2.1.3) says Hermes killed him with a thrown stone because Hierax had betrayed the plan. Ovid (Metamorphoses 1.650-711 and 1.712-746) has Mercury lull all his eyes to sleep with pipes and the tale of Syrinx, then behead him with a curved sword. Aeschylus (Prometheus Bound 680) speaks only of a sudden, unexpected death, and in Suppliants (291-315) the King says Hermes slew him.
- What tormented Io differs. Apollodorus and Aeschylus name a gadfly sent by Hera. Ovid (Metamorphoses 1.712-746) describes a Fury planted in her mind by Juno. Aeschylus (Prometheus Bound 566-570) has Io see the gadfly as the ghost of the dead Argus still pursuing her.
- Her route differs. Apollodorus (Library 2.1.3) takes her to the Ionian gulf, Illyria, Mount Haemus, the Bosporus, Scythia and the Cimmerian land. Aeschylus's Suppliants (538-589) leads her through Asia Minor. Prometheus Bound (700-740, 786-815) foretells a route east past the Caucasus and the Amazons, then to the Graeae, the griffins and the Arimaspians before the Nile, and (823-845) recalls an earlier passage by Dodona and the gulf named Ionian after her.
- Herodotus (Histories 1.1-1.2 and 1.5) gives two rationalised accounts with no gods: the Persians say Phoenician traders carried Io off to Egypt, while the Phoenicians say she left willingly after becoming pregnant by the ship's captain. Herodotus reports both without deciding between them.
- The identification of Io with Isis and of Epaphus with Apis is Greek interpretation. Herodotus (Histories 2.41) notes only that Isis was pictured horned like Io, and names Apis as Epaphus (2.153). Apollodorus (Library 2.1.3) says the Egyptians called Io Isis.
Sources
- Apollodorus, Library 2.1.3
- Apollodorus, Library 2.1.4
- Apollodorus, Library 2.5.11
- Apollodorus, Library 3.1.1
- Aeschylus, Prometheus Bound 566-570
- Aeschylus, Prometheus Bound 640-685
- Aeschylus, Prometheus Bound 700-740
- Aeschylus, Prometheus Bound 757-780
- Aeschylus, Prometheus Bound 786-815
- Aeschylus, Prometheus Bound 823-845
- Aeschylus, Prometheus Bound 846-875
- Aeschylus, Suppliants 15-20
- Aeschylus, Suppliants 291-315
- Aeschylus, Suppliants 538-589
- Ovid, Metamorphoses 1.583-649
- Ovid, Metamorphoses 1.650-711
- Ovid, Metamorphoses 1.712-746
- Ovid, Metamorphoses 1.746-750
- Ovid, Metamorphoses 2.531-533
- Herodotus, Histories 1.1-1.2
- Herodotus, Histories 1.5
- Herodotus, Histories 2.41
- Herodotus, Histories 2.153
- Ovid, Metamorphoses 2.466-530