The AoL backstory of Zelda being put into an eternal sleep by a Wizard hired by the Prince happened a long time before AoL itself. These events happened shortly after the King of Hyrule who used the ENTIRE Triforce to govern Hyrule died and told the secrets of the Triforce to Zelda alone.

In the Oracle games opening sequences, we see Link ride to Hyrule Castle on a horse, and enter a chamber containing the entire Triforce. This means the Triforce was in the possession of the Royal Family at the time of the Oracles, and likely around this time the AoL backstory of Zelda being put into an eternal sleep occured.

As to why every Princess of Hyrule before these events happened is unknown, but you are most likely right, Historian, about Royal Family's reusing the same name over and over, which would explain why all the princesses are named Zelda before the Zelda in AoL was put into her eternal sleep.

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