[...] I do not wish actually to influence your conception of an overture to Romeo and Juliet, but I would rather like to express a wish that before going farther you would read a dissertation on the Coriolanus Overture which I have written for our public, for the better understanding of a performance of this composition, and which I shall soon send you in print. I was delighted to find that this entire piece of music is nothing else but the accompaniment to a dramatic—almost pantomimic—scene between Coriolanus and his mother in the camp before Rome. You should condense the whole poem of Romeo and Juliet into a similar dramatic moment. Straying farther and farther on the philosophic plane as you are doing, your music can only become more and more incomprehensible. For—once again—absolute music can only express feelings, passions and moods in their antitheses and intensities, it cannot express any kind of relationships of a political or social nature. Beethoven had a magnificent instinct for this. I almost prefer as an artistic conception his poem of Coriolanus with its dramatic unity and terseness, whereby the subject attains in a sense the objective nature of a myth, to the Shakespearian poem. [...]
Source: Letters of Richard Wagner, Vol. 1, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 211