The Sacred Realm is the location where the Goddesses departed the world at the end of Creation. The creation myth details that the Sacred Realm "came to be known as The Sacred Realm" implying that it was a name given after the fact.
Location
The Temple of Hylia
Prior to the battle with Demise, the Triforce resided in the Temple of Hylia. Following the battle with Demise, Hylia raised the land that sat over top of what would become the Sealed Grounds and sent it to the sky along with the Triforce.
The Sky
During the events of The Legend of Zelda: Skyward Sword, it's revealed that the Triforce was hidden in the Sky Keep, accessible only once the hero proved themselves worthy of it.
The Return to the Surface
At the end of the Sky Era, Zelda returned to the Surface to protect the Triforce. The exact location that she hid the Triforce during that time is unknown, but it is assumed that it remained at the Temple of Hylia and continued to remain there until Rauru built the Temple of Light to safeguard it.
The Temple of Light
The exact location of the Sacred Realm is a subject that researchers and treasure seekers have wondered about throughout the history of Hyrule. According to accounts during the Era of Chaos, the Sacred Realm was sealed by Rauru and the Temple of Light was built in the center of the Sacred Realm to protect the Triforce. The Legend of Zelda: Tears of the Kingdom Masterworks revealed that the Temple of Light resides over top of the Sealed Grounds, implying that the Sacred Realm actually resides in a subterranean area.
The Creation Myth
Before time began, before spirits and life existed... Three golden goddesses descended upon the chaos that was Hyrule... Din, the goddess of power... Nayru, the goddess of wisdom... Farore, the goddess of courage.... Din...With her strong flaming arms, she cultivated the land and created the red earth. Nayru... Poured her wisdom onto the earth and gave the spirit of law to the world. Farore...With her rich soul, produced all life forms who would uphold the law. The three great goddesses, their labors completed, departed for the heavens. And golden sacred triangles remained at the point where the goddess left the world. Since then, the sacred triangles have become the basis of our world’s providence. And, the resting place of the triangles has become the Sacred Realm[1].
Era of Chaos
The Light Spirits Banish the Interlopers
After sealing the magic of the Interlopers into the Fused Shadow, the Light Spirits Lanayru, Faron, Eldin, and Ordona chased the group through Hyrule, culminating with the Interlopers getting banished to the Twilight Realm via the Mirror of Twilight[2]
Rauru Seals the Sacred Realm
The legend of a supreme power spread throughout the land, whetting the appetites of those who would possess the Triforce and inciting vicious battles between them. Rauru, the Sage of Light, constructed the Temple of Time, which contained the only existing entrance to the Sacred Realm, where the Triforce was located. With power stronger than both time and the Master Sword, Rauru sealed the Sacred Realm. The pedestal holding the Master Sword was closed behind the Door of Time, and the keys to opening the door (the Spiritual Stones of forest, fire, and water) were protected by their respective people[3]
- ↑ The Great Deku Tree shares the creation myth, The Creation Myth, (The Legend of Zelda: Ocarina of Time, 1998)
- ↑ The Light Spirits Banish the Interlopers, The Legend of Zelda: Hyrule Historia (January 29, 2013). Nintendo. Dark Horse Books. p. 113
- ↑ Rauru Seals the Sacred Realm, The Legend of Zelda: Hyrule Historia (January 29, 2013). Nintendo. Dark Horse Books. p. 77