In Greek mythology, Io was a young woman who was loved by Zeus, king of the gods. His attentions toward her aroused the jealousy of his wife, HeraGreek goddess, wife and sister of Zeus; queen of heaven (Roman goddess Juno), and both deitiesgod or goddess used their powers in various ways to try to gain control over Io.

The daughter of the river god Inachus, Io was a priestess at one of Hera's temples. Zeus fell in love with her and seduced her. When Hera learned about Zeus's behavior, she turned the girl into a white cow. In some versions of the myth, it was Zeus who transformed Io into the cow, to conceal her from Hera.

After tying Io the cow to an olive tree, Hera sent Argus, a giant with 100 eyes, to watch over her. Zeus responded by sending the messenger god Hermes to rescue Io. Hermes put Argus...