This engraving, found in Athanasius Kircher's two volume work on music, depicts Orpheus playing the hellhound Cerberus to sleep in order to gain passage to the Underworld. In classical sources, Cerberus was not usually so easily tamed: to the Greeks, he was a monstrous three-headed dog. A glance at Cerberus was said to petrify humans, and his bite was poisonous. Most Greek sources describe Cerberus as possessing three heads, as does Fluffy, the fearsome guard dog who blocks passage to the underground vault guarding the philosopher's stone. Spoiler alert: Harry and his friends take a cue from Orpheus's book and soothe Hogwarts' vicious pup by picking a drowsy tune.