Sarah Siddons as the Tragic Muse paintings of Melpoméne, she is represented with a tragic mask and also often holds in her other hand a knife or club. In Greek mythology, she is the daughter of Zeus and Mnemosyne, who had eight other daughters, Melpoméne's sisters and the eight other muses are: Calliope, muse of epic poetry; Clio, muse of history; Euterpe, muse of flute playing; Terpsichore, muse of dancing; Erato, muse of erotic poetry; Thalia muse of comedy; Polyhymnia, muse of hymns; and Urania, muse of astronomy. Reynolds was inspired not only by Sarah Siddons' extreme talent to embody the tragic heroine in Macbeth, but
Muses and Avestan "Mazda". The Muses, therefore, were both the embodiments and sponsors of performed metrical speech: "mousike" (whence the English term "music") was just "one of the arts of the Muses". Others included Science, Geography, Mathematics, Philosophy, and especially Art, Drama, and inspiration. In the archaic period, before the widespread availability of books (scrolls), this included nearly all of learning. The first Greek book on astronomy, by Thales, took the form of dactylic hexameters, as did many works of pre-Socratic philosophy. Both Plato and the Pythagoreans explicitly included philosophy as a sub-species of "mousike". The "Histories" of Herodotus, whose primary