As told in Ocarina of Time:

"Long ago, there was a kingdom where a golden power lay hidden. It was a prosperous land blessed with green forests, tall mountains, and above all, it was in peace, as it had been for ages. But one day, a man of great evil lay his hands upon the golden power and attemtped to satisfy his evil intentions with it. With its strength at his command, he spread darkness across the kingdom. But then, when all hope had died, and the hour of doom seemed at hand, a young boy clothed in green appered out of nowhere. Wielding the Blade of Evil's Bane, He sealed the King of Evil away and returned the light to the land. This boy, rumored to have used the ability to travel through time to save the land was known as the Hero of Time. The boy's tale was passed down through generations, and as we speak he has become a Legend...."