The Pierides.
    Nine maidens of Pieria, birthplace of the Muses and site of Mount Olympus, the Pierides were preeminent in song. So proud were they of their numbers and their talent that they traveled to Mount Helicon and challenged the Heliconian Muses to a singing contest. According to Ovid, who call the Pierides daughter of Pierus of Pella, the Pierides sang of the battle of the gods and giants, and Calliope, representing the Muses, sang of the rape of Persephone (Proserpine) and Demeter's (Ceres') search. The Muses won easily. When the Pierides responded by reviling the victors, they were changed into chattering magpies.