Muses, in Greek mythology, were goddesses who inspired poets and protected art, letters, and science. They were nine in number - Calliope, the muse of epic poetry; Clio, of history; Melpomene, of tragedy; Thalia, of comedy; Euterpe, of lyric poetry; Erato, of erotic poetry; Polyhymnia, of the sacred hymns; Terpsichore, of choral song and dance; and Urania, of astronomy. They were usually represented as the daughters of Zeus and Mnemosyne. [Memory.] The chief seats of their worship were Mount Olympus in Thessaly, with the district of Pieria, which lies N. of it, and the neighbourhood of Thespiae and Ascra on Mount Helicon.