THE MOUSAI (Muses) were the goddesses of music, song, and dance, and the source of inspiration to poets. They were also goddesses of knowledge, who remembered all things that had come to pass. Later the Mousai were assigned specific artistic spheres: Kalliope (Calliope), epic poetry; Kleio (Clio), history; Ourania (Urania), astronomy; Thaleia (Thalia), comedy; Melpomene, tragedy; Polymnia (Polyhymnia), religious hymns; Erato, erotic poetry; Euterpe, lyric poetry; and Terpsikhore (Terpsichore), choral song and dance.

In ancient Greek vase paintings, the Mousai were depicted as beautiful young women with a variety of musical instruments. In later art, each of the nine was assigned her distinctive attribute.

There were two alternative sets of Mousai--the three or four Mousai Titanides and the three Mousai Apollonides.