The date of this famous letter was 1767, but after Alceste Gluck was still able to use material from earlier work; and the overture to Armide is adapted from that of Telemacco, written in the year of Bach's death (1750).
- Mozart's full symphonic scheme requires the string-band, I flute (rarely 2), 2 oboes, 2 clarinets (whenever he could obtain them, he being the first composer who really appreciated them, instead of regarding them either as cheap substitutes for the clarino or high trumpet of Bach, or, like Gluck and, with rare and late exceptions, Haydn, as merely adding to the force of tutti passages).
The elaborate choral writing sometimes rises to almost Hellenic regions of dramatic art; and there is no crudeness in the passages that carry on the story quietly in reaction from the climaxes - a test far too severe for Tannhauser and rather severe for even the mature works of Gluck and Weber.
Between these dates Houdon had not been idle; busts of Catharine II., Diderot and Prince Galitzin were remarked at the Salon of 1773, and at that of 1775 he produced, not only his Morpheus in marble, but busts of Turgot, Gluck (in which the marks of small-pox in the face were reproduced with striking effect) and Sophie Arnould as Iphigeneia (now in the Wallace Collection, London), together with his well-known marble relief, "Grive suspendue par les pattes."
His interest in music led to his acquaintance with the composer Gluck, who became his intimate friend.