The Muses Clio, Thalia, Terpsichore, Euterpe, Polyhymnia, Calliope, Erato, Urania, and Melpomene on a Roman sarcophagus.
In Greek mythology, the Muses were divinities originally included amongst the Nymphs, but afterwards regarded as quite distinct from them. To the Muses was ascribed the power of song, and poets and musicians were therefore regarded as their pupils and favorites. They were first honored amongst the Thracians, and, as Pieria around Olympus was the original seat of that people it came to be considered as the native country of the Muses, who were therefore called Pierides.
In the earliest period their number was three, though Homer sometimes speaks of a single muse, and once, at least, alludes to nine. This last in the number given by Hesiod in his Theogony, who also mentions their names – Clio, the muse of history; Euterpe, of lyric poetry; Thalia, of comedy; Melpomene, of tragedy; Terpischore (Gr., "delighting in the dance"), of choral dance and song; Erato, of erotic poetry; Polyhymia, of the sublime hymn; Urania, of astronomy; and Calliope, of epic poetry. Their origin is differently given, but the most widely-spread account represented them as the daughters of Zeus and Mnemosyne. Homer speaks of them as the goddesses of song, and as dwelling on the summit of Olympus. They are also often represented as the companions of Apollo, and as singing while he played upon the lyre at the banquets of the Immortals. Various legends ascribed to them victories in musical competitions, particularly over the Sirens. In the later classic times particular provinces were assigned to them in connection with different departments of literature, science, and the fine arts; but the invocations addressed to them appear to have been, as in the case of modern writers, merely formal imitations of the earlier poets.
Their worship amongst the Romans was a mere imitation of the Greeks, and never became truly national or popular. Among the places sacred to them were the fountains of Aganippe and Hippocrene on Mount Helicon, and the Castalian spring on Mount Parnassus.