Ouranos (or Uranus, as the Romans knew him) was the Greek sky god. He was a Protogenoi, one of the earliest gods. His consort was Gaia, who was usually either his sister or mother. He was father to the Titans . He ruled the gods until he was overthrown by five of his sons, Cronus , Hyperion , Iapetus , Coeus and Crius. Gaia conspired with them to overthrow Ouranos because he cast their (his and Gaia's) children, the Cyclopes and the Hekatonchieres into Tartarus. When he died he cursed his son and usurper, Cronus, to be overthrown by his own children (Ouranos' grandchildren), who became six out of theTwelve Olympians.