He showed, in a few words, that it is not sufficient to throw together a few incidents that are to be met with in every romance, and that to dazzle the spectator the thought should be new, without being farfetched; frequently sublime, but always natural; the author should have a thorough knowledge of the human heart and make it speak properly; he should be a complete poet, without showing an affectation of it in any of the characters of his piece; he should be a perfect master of his language, speak it with all its pruity and with the utmost harmony, and yet so as not to make the sense a slave to the rhyme. Whoever, added he, neglects any one of these rules, though he may write two or three tragedies with tolerable success, will never be reckoned in the number of good authors.
~ Voltaire