The simple fact that Gluck in beginning his labor of reform in opera selected for the subject of his libretto the story used by Rinuccini and Peri in "Euridice" shows that he embarked upon his undertaking with a sincere desire to get at the fundamental principles of the true _drama per musica_. From the miserable incongruity of his own "Piramo e Tisbe" he proceeded to the conviction that the ultimate purpose of opera music must be a correct and moving embodiment of the emotions expressed by the text. The methods which he regarded as efficient are best enumerated by himself in the preface to his "Alceste." He says:-- "I endeavored to reduce music to its proper function, that of seconding poetry by enforcing the expression of the sentiment and the interest of the situations without interrupting the action, or weakening it by superfluous ornament. My idea was that the relation of music to poetry was much the same as that of harmonious coloring and well disposed light and shade to an accurate drawing, which animates the figures without altering the outlines. I have therefore been very careful never to interrupt a singer in the heat of a dialogue in order to introduce a tedious ritornelle, nor to stop him in the middle of a piece either for the purpose of displaying the flexibility of his voice on some favorable vowel, or that the orchestra might give him time to take breath before a long-sustained note. "Furthermore I have not thought it right to hurry through the second part of a song, if the words happened to be the most important of the whole, in order to repeat the first part regularly four times over; or to finish the air where the sense does not end in order to allow the singer to exhibit his power of varying the passage at pleasure. In fact my object was to put an end to abuses against which good taste and good sense have long protested in vain. "My idea was that the overture ought to indicate the subject and prepare the spectators for the character of the piece they are about to see; that the instruments ought to be introduced in proportion to the degree of interest and passion in the words; and that it was necessary above all to avoid making too great a disparity between the recitative and the air of a dialogue, so as not to break the sense of a period or awkwardly interrupt the movement and animation of a scene. I also thought that my chief endeavor should be to attain a grand simplicity, and consequently I have avoided making a parade of difficulties at the cost of clearness. I have set no value on novelty as such, unless it was naturally suggested by the situation and suited to the expression. In short, there was no rule which I did not consider myself bound to sacrifice for the sake of effect."