The painting depicts a scene from Ovid's Metamorphoses, which tells of Minerva visiting the muses on Mount Helicon, to listen to their song and see the Hippocrene.

[...] Pallas, after she had long admired that fountain, flowing where the hoof had struck, turned round to view the groves of ancient trees; the grottoes and the grass bespangled, rich with flowers unnumbered—all so beautiful she deemed the charm of that locality a fair surrounding for the studious days of those Mnemonian Maids.

[4] As mentioned by Ovid, according to tradition, Pegasus and his brother Chrysaor sprang from the blood issuing from Medusa's neck as Perseus was beheading her.

After beheading her, Perseus used Medusa's head, which retained its ability to turn onlookers to stone, as a weapon, and then gave it to Athena (Minerva) who placed it on her shield.

The scene does not take place on the Parnassus, but on the Helicon, as evinced in the Hippocrene, "Horse's Fountain", stemming from beneath Pegasus's hooves.