In Cervantes’ Coloquio de los perros (published 1613), a dog recounts all the colorful characters he’s met in his life. One is this frustrated poet: “I have strictly observed the rule laid down by Horace in his Poetica not to bring to light any work until ten years after it has been composed. Now I have a work on which I was engaged for twenty years, and which has lain by me for twelve […] a lofty, sonorous, heroic poem, delectable and full of matter; and yet I cannot find a prince to...