Meanwhile, Gluck was at work upon his _Alceste_, and Sophie had every reason to believe that, after her brilliant triumph in _Iphigénie_ and her very successful rendering of the part of Eurydice, she would again be cast for the principal rôle. But alas! a bitter disappointment was in store for her. We have mentioned that Rosalie Levasseur was the mistress of Mercy-Argenteau, the Austrian Ambassador at the French Court. Shrewd and capable though Mercy was in everything relating to his professional duties--the manner in which he had succeeded in keeping the peace, and all that it involved, between Marie Antoinette and Madame du Barry, during the last years of the late King’s reign was a perfect masterpiece of diplomacy--in love, he appears to have been as foolish as any of the gilded youths who haunted the _coulisses_ of the Opera and the Comédie-Française. The fair Rosalie exercised the most absolute ascendency over him--a fact which was the more astonishing, as all Paris knew that she had an _amant de cœur_, in the person of Nicolet, the clown. Mercy, in fact, could deny her nothing, and even carried his infatuation so far as to purchase for her a barony of the Holy Roman Empire, with a considerable revenue; while, on another occasion, he condescended to bribe Larrivée, whose singing in a certain opera the young lady found was quite eclipsing her own, not to put forth his full powers.[52] Now, Rosalie had set her heart upon supplanting Sophie and filling the principal part in the forthcoming opera, and called upon her lover to assist her to realise her ambition. First, she suggested--or persuaded Mercy to suggest--that Gluck should take up his quarters in her house, in the Rue des Fossoyeurs-Saint-Germain, and give her singing-lessons; a proposal to which the composer, who, besides being an Austrian subject, was under considerable obligations to the Ambassador, who, with Marie Antoinette, had been mainly instrumental in bringing him to Paris, readily consented. Next, she induced him to teach her the music of _Alceste_ and took care to show herself a docile as well as an industrious pupil. Finally, she hinted pretty plainly that he ought to entrust her with the title-part when the opera was produced, pointing out that, though she might lack the histrionic ability of Mlle. Arnould, her voice was fresher and more powerful, to say nothing of the advantage which the composer would derive from having the part rendered exactly as he desired, whereas the elder actress would very probably insist on rendering it in conformity with her own ideas. These arguments were, it is needless to say, warmly seconded by Mercy; and Gluck, who was anxious to please the amorous diplomatist, and in whose mind the insult he had received from Sophie’s titular protector perhaps still rankled, after some hesitation, yielded to their wishes.