Ouranos was the primal Greek god personifying the sky. In Ancient Greek literature, according to Hesiod in his Theogony, Ouranos or Father Sky was the son and husband of Gaia, Mother Earth. Ouranos and Gaia were ancestors of most of the Greek gods, but no cult addressed directly to Ouranos survived into classical times. Ouranos does not appear among the usual themes of Greek painted pottery. Elemental Earth, Sky and Styx might be joined, however, in a solemn invocation in Homeric epic.
In the Olympian creation myth, Ouranos came every night to cover the earth and mate with Gaia, but he hated the children she bore him. Hesiod named their first six sons and six daughters the Titans, the three one-hundred-armed giants the Hekatonkheir, and the one-eyed giants the Cyclopes.
Ouranos imprisoned Gaia's youngest children in Tartarus, deep within Earth, where they caused pain to Gaia. She shaped a great flint-bladed sickle and asked her sons to castrate Ouranos. Only Cronus, youngest and most ambitious of the Titans, was willing: he ambushed his father and castrated him, casting the severed testicles into the sea. For this fearful deed, Ouranos called his sons Titanes Theoi, or "Straining Gods."From the blood that spilled from Ouranos onto the Earth came forth the Gigantes, the Erinyes (the avenging Furies), the Meliae (the ash-tree nymphs), and, according to some, the Telchines.
After Ouranos was deposed, Cronus re-imprisoned the Hekatonkheires and Cyclopes in Tartarus. Ouranos and Gaia then prophesied that Cronus in turn was destined to be overthrown by his own son, and so the Titan attempted to avoid this fate by devouring his young. Zeus, through deception by his mother Rhea, avoided this fate.