Hades (; from Greek  (older form Ἀϝίδης), Hadēs, originally , Haidēs or , Aidēs (Doric Ἀΐδας Aidas), meaning "the unseen") was the ancient Greek god of the underworld. The genitive , Haidou, was an elision to denote locality: "[the house/dominion] of Hades". Eventually, the nominative came to designate the abode of the dead. In Greek mythology, Hades is the oldest male child of Cronus and Rhea. According to myth, he and his brothers Zeus and Poseidon defeated the Titans and claimed rulership over the cosmos, ruling the underworld, air, and sea, respectively; the solid earth, long the province of Gaia, was available to all three concurrently.