This is the beginning and root to the “Legend of Zelda”. Here is where the legend about the Triforce first made its appearance. This legend was handed down from one generation to next for a very long time. The “Age of Chaos” period lasts until Ganon and his henchmen invaded Hyrule and obtained the Triforce of Power, it is after this period that Link starts his quest to bring peace back to Hyrule.
Taken from LoZ’s Manual: