The passions, whether violent or not, should never be so expressed as to reach the point of causing disgust; and music, even in situations of the greatest horror, should never be painful to the ear but should flatter and charm it, and thereby always remain music.

Letter by Mozart, as quoted in a journal entry (12 December 1856) The Journal of Eugene Delacroix as translated by Walter Pach (1937), p. 521.