Note 1 — Chapter I · PREFACE, PRELUDE, PROLOGUE, INTRODUCTION, OVERTURE, ETC.—THE ORIGIN OF THE OPERA IN ITALY, AND ITS INTRODUCTION INTO GERMANY.—ITS HISTORY IN EUROPE; DIVISION OF THE SUBJECT.
Reading edition
Wagner calls the composer of an opera "the sculptor or upholsterer," (which is complimentary to sculptors,) and the writer of the words "the architect." I would rather say that the writer of the words produces a sketch, on which the composer paints a picture.
Since writing the above I find that the greatest of French poets describes an admirable libretto of his own as "un canevas d'opéra plus ou moins bien disposé pour que l'œuvre musicale s'y superpose heureusement;" and again, "une trame qui ne demande pas mieux que de se dérober sous cette riche et éblouissante broderie qui s'appelle la musique." (Preface to Victor Hugo's Esmeralda.)