The History of the Zora, Part Four is a Monument, and a location you need to visit for the quest Zora Stone Monuments.
The Lightscale Trident As told by King Dorephan
The queen and I were blerssed with a daughter as lovely as a jewel. We named our princess... Mipha. To celebrate her birth, the smithy Dento present Mipga with a gift: a mighty spear called the Lightscale Trident. Mipha grew into a bright girl and soon reached the age of receiving lesson from the royal family's order of knights. The whole of the royal knights adored her, especially Sergeant Seggin, who lived her as if she were his own kin. Under Seggin's instruction, Mipha honed her skills, and her radiance grew along with her skill with the Lightscale Trident. As a Champion, Mipha made her people proud. However, once the Great Calamity struck, she was never to return. All of Zora's Domain fell into misery. The merest thought of the princess was enough to overcome anyone with tears. As a way of offering her soul repose, they tried to send the Lightscale Trident drifting down the Zora River. But when they did, the trident began to glow, and Mipha's voice rang loud and clear for all Zora to hear: "The Lightscale Trident and I are one... Abandon your grief and know joy once again. Do not cry, just remember." And so, keeping to her request, on the day of the Great Calamity... the day that Mipha passed from this world... the Zora venerate the Lightscale Trident and remember their brave princess. Such is the origin of the Champion Festival.