The music of 'Idomeneo' is cast for the most part in Italian form, though the influence of Gluck is obvious in many points, particularly in the scene of the oracle. Here we find Mozart in his maturity for the first time; he has become a man, and put away childish things. In two points 'Idomeneo' is superior to any opera that had previously been written--in the concerted music (the choruses as well as the trios and quartets), and in the instrumentation. The chorus is promoted from the part which it usually plays in Gluck, that of a passive spectator. It joins in the drama, and takes an active part in the development of the plot, and the music which it is called upon to sing is often finer and more truly dramatic than that allotted to the solo singers. But the chorus had already been used effectively by Gluck and other composers; it is in his solo concerted music that Mozart forges ahead of all possible rivals. The power which he shows of contrasting the conflicting emotions of his characters in elaborate concerted movements was something really new to the stage. The one quartet in Handel's 'Radamisto' and the one trio in his 'Alcina,' magnificent as they are, are too exceptional in their occurrence to be quoted as instances, while the attempts of Rameau and his followers to impose dramatic significance into their concerted music, though technically interesting, do but faintly foreshadow the glory of Mozart. The orchestration of 'Idomeneo,' too, is something of the nature of a revelation. At Munich, Mozart had at his disposal an excellent and well-trained band, and this may go far to explain the elaborate care which he bestowed upon the instrumental side of his opera. The colouring of the score is sublime in conception and brilliant in detail. Even now it well repays the closest and most intimate study. 'Idomeneo' is practically the foundation of all modern orchestration. Mozart's next work was very different both in scope and execution. It has already been pointed out that the two first works which the composer, as a child, wrote for the stage, followed respectively the Italian and German models. Similarly, he signalised his arrival at the full maturity of his powers by producing an Italian and German masterpiece side by side. 'Die Entfuehrung aus dem Serail' was written for the Court Theatre at Vienna, in response to a special command of the Emperor Joseph II. It was produced on July 13, 1782. The original libretto was the work of C.F. Bretzner, but Mozart introduced so many alterations and improvements into the fabric of the story that, as it stands, much of it is practically his own work.