The four frescoes by Raphael in the Stanza della Segnatura in the Vatican Museum visually embody close approximations of several numerical ratios that are of deep significance in the material grounding of musical harmonies in the physics of natural harmonics. Of special significance is the Pythagorean musical frequency ratio of 9:8, the (discordant) whole tone interval, which in Plato's Timaeus is called the epogdoôn (‘and an eighth’).