The painting shows the moment described in Ovid’s Metamorphoses when the mythical winged horse Pegasus stamped his hoof on Mount Helicon, causing a spring to gush forth. The spring became known as the Hippocrene, or Spring of the Horse. Here the artist shows several thin streams flowing down to feed a larger body of water in the plain. Surrounding Pegasus are the Muses, singing and making music, while the daughters of Pierus, who sang in contest with them, stand in a circle in the background. The painting was probably the lid of a keyboard instrument. The nine Muses all wear Lombard costume of around 1540, which is similar to that in Romanino’s murals in Palazzo Salvadego, Brescia, of about 1543. The facial types are also typical of Romanino as are the short, curled shading lines beneath the arm of the man to the left.