Marius Petipa's libretto was based on the scenario of the danced tableau La Pérégrina: Ballet de la Reine from Verdi's opera Don Carlos, which was never performed and was to have been choreographed by Petipa's brother Lucien [REF].
La Perle is set in a colossal subterranean grotto where the White Pearl, the most precious pearl on Earth, resides with her sister pearls of differing colors.