The Zelda timeline starts several thousands of years before Skyward Sword, with the goddess Hylia creating the golden goddesses (Din, Nayru, and Farore), who then create Hyrule, leaving behind the sacred relic known as the Triforce, which can grant the wish of anyone who uses it. Though, this essentially opens Pandora's Box for all the local demons and crackheads to try and nab it. One such character, known as Demise, tries to steal the Triforce, but is thwarted by Hylia's chosen hero. To keep the Triforce safe, Hylia sent the Hylians onto a piece of land, later to be appropriately named Skyloft, into the sky, leaving the non-minorities (Gorons and adjacent species) on the surface below. She then seals Demise for years and years. (there's more where this came from)