Io

In Greek mythology, Io (/ˈaɪ.oʊ/; Ancient Greek: Ἰώ [iːɔ̌ː]) was one of Zeus's mortal lovers. An Argive princess, she became an ancestor to numerous kings and heroes, including Perseus, Cadmus, Heracles, Minos, Lynceus, Cepheus, and Danaus. In 1614, astronomer Simon Marius named a moon of Jupiter after her.

As the sister of Phoroneus, Io is also known as Phoronis (an adjectival form meaning "Phoronean"). She was occasionally compared to the Egyptian goddess Isis, while her Egyptian husband Telegonus was associated with Osiris.

Most legends identify Io as the daughter of Inachus, though alternative genealogies exist. If Inachus was indeed her father, her mother would presumably have been his wife (and sister), the Oceanid nymph Melia, daughter of Oceanus. As Inachus's daughter, she carried the patronymic Inachis (Ἰναχίς).

The Catalogue of Women and Acusilaus named Io's father as Peiren, possibly a son of the elder Argus, also known as Peiras, Peiranthus, or Peirasus. This connection suggests Io might be the same figure as Callithyia, daughter of Peiranthus, as proposed by Hesychius of Alexandria.

The 2nd century AD geographer Pausanias mentions another, later Io, a descendant of Phoroneus and daughter of Iasus. This Iasus was either the son of Argus and Ismene (daughter of Asopus), or of Triopas and Sosis, in which case Io's mother was Leucane.