Theia was a Titan. The name Theia alone means simply, "goddess"; Theia Euryphaessa (Θεία Εὐρυφάεσσα) brings overtones of extent (εὐρύς eurys "wide", root: εὐρυ-/εὐρε-) and brightness (φάος phaos "light", root: φαεσ-).
Robert Graves relates[2] that in the Pelasgian creation myth, she was the child of Eurynome—the creator called the goddess of all things—who created Theia as a Titaness ruling the sun. Hesiod's Theogony gives her an equally primal origin, a daughter of Gaia (Earth) and Uranos (Sky).[3] In 42.a Graves also relates that later Theia is referred to as the cow-eyed Euryphaessa who gave birth to Helios, the sun.[4]
Once paired in later myths with her Titan brother Hyperion as her husband, "mild-eyed Euryphaessa, the far-shining one" of the Homeric Hymn to Helios, was said to be the mother of Helios (the Sun), Selene (the Moon), and Eos (the Dawn).
Pindar praises Theia in his Fifth Isthmian ode:
Mother of the Sun, Theia of many names, for your sake men honor gold as more powerful than anything else; and through the value you bestow on them, o queen, ships contending on the sea and yoked teams of horses in swift-whirling contests become marvels.
She seems here a goddess of glittering in particular and of glory in general, but Pindar's allusion to her as "Theia of many names" is telling, since it suggests assimilation, referring not only to similar mother-of-the-sun goddesses such as Phoebe and Leto, but perhaps also to more universalizing mother-figures such as Rhea and Cybele.