In Greek mythology, the Pierian Spring of Macedonia was sacred to the Pierides and the Muses. As the metaphorical source of knowledge of art and science, it was popularized by a couplet in Alexander Pope's 1711 poem An Essay on Criticism: "A little learning is a dang'rous thing; / Drink deep, or taste not the Pierian spring."
The Pierian spring is sometimes confused with the Castalian Spring, as it was by Lord Chesterfield who misquotes Alexander Pope in Letters to His Son.[1]