The Orphic Hymns

you who revealed the rites of the mysteries to mortals: Kleio, Euterpe, Thaleia, Melpomene, Terpsichore, Erato, Polymnia and Ourania, with Kalliope the mother, and Eunomia, holy goddess.

The Muses "revealed the rites of the mysteries to mortals." Greeks usually gave that credit to Orpheus: in Aristophanes' Frogs the poet Aeschylus says that "Orpheus showed us the rites," with a verb of the same family. The two claims meet in the list of names. Eight Muses are named one after another, and the ninth apart from them, "with Kalliope the mother." Kalliope was the mother of Orpheus, in whose voice these hymns are spoken. The phrase can also be read "Kalliope, with their mother," meaning Memory, but in a book spoken by Orpheus "the mother" is most likely Kalliope herself.