Muse, Greek Mousa or Moisa, Latin Musa, in Greco-Roman religion and mythology, any of a group of sister goddesses of obscure but ancient origin, the chief centre of whose cult was Mount Helicon in Boeotia, Greece. They were born in Pieria, at the foot of Mount Olympus. Very little is known of their cult, but they had a festival every four years at Thespiae, near Helicon, and a contest (Museia), presumably—or at least at first—in singing and playing.