Pierian Spring
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.