this led to the frequent "Castle, interior". Battles take place off stage. Unity of time: ideally the entire play should take place in 24 hours. Unity of action: there should be one central story and all secondary plots should be linked to it. Although based on classical examples, the unities of place and time were seen as essential for the spectator's complete absorption into the dramatic action; wildly dispersed scenes in China or Africa, or over many years would—critics maintained—break the theatrical illusion. Sometimes grouped with the unity of action is the notion that no character should appear unexpectedly late in the drama. Linked with the theatrical unities are the following concepts: "Les bienséances": literature should respect moral codes and good taste; nothing should be presented that flouts these codes, even if they are historical events. "La vraisemblance": actions should be believable. When historical events contradict believability, some critics counselled the latter. The criterion of believability was sometimes also used to criticize soliloquy, and in late classical plays characters are almost invariably supplied with confidents (valets, friends, nurses) to whom they reveal their emotions. These rules precluded many elements common in the baroque "tragi-comedy": flying horses, chivalric battles, magical trips to foreign lands and the deus ex machina. The mauling of Hippolyte by a monster in Phèdre could only take place offstage. Finally, literature and art should consciously follow Horace's precept "to please and educate" ("aut delectare aut prodesse est"). These "rules" or "codes" were seldom completely followed, and many of the century's masterpieces broke these rules intentionally to heighten emotional effect: Corneille's "Le Cid" was criticised for having Rodrigue appear before Chimène after having killed her father, a violation of moral codes. Theatre under Louis XIV By the 1660s, classicism had finally imposed itself on French theatre. The key theoretical work on theatre from this period was François Hedelin, abbé d'Aubignac's "Pratique du théâtre" (1657), and the dictates of this work reveal to what degree "French classicism" was willing to modify the rules of classical tragedy to maintain the unities and decorum (d'Aubignac for example saw the tragedies of Oedipus and Antigone as unsuitable for the contemporary stage). Although Pierre Corneille continued to produce tragedies to the end of his life, the works of Jean Racine from the late 1660s on totally eclipsed the late plays of the elder dramatist. Racine's tragedies—inspired by Greek myths, Euripides, Sophocles and Seneca—condensed