Of Mozart’s symphonies and serenades, terms which in some cases are practically synonymous, there are about eleven that are of lasting value and at least three that are imperishable. With the exception of the Paris symphony, ‘a brilliant and charming _pièce d’occasion_,’ which was referred to above, all of them were written during the Vienna period, and the three great ones flowed from the composer’s pen within the brief space of six weeks in 1787, the year of _Don Giovanni_. In the matter of form again Mozart followed in the tracks of the Mannheim school. The usual three movements remain, but, like Haydn, he usually adds the minuet after the slow movement. The ‘developed ternary form’ is applied in the first and more and more frequently also in other movements, especially the last, where it takes the place of the lighter rondo. But the musical material is richer and its handling far more ingenious than that of his predecessors, just as the spiritual import is much deeper. The movements are more closely knit, they have a unity of emotion which clearly points in the direction of Beethoven’s later works. There is, if not an _idée fixe_, at any rate a _sentiment fixe_. It is manifested in a multiplicity of ways: more consistent use of the principal thematic material in the ‘working-out,’ reassertion of themes after the ‘transition’ (the section leading from the exposition to the development), introductions which are, as it were, improvisations on the mood of the piece, and codas ‘summing up’ the subjective matter. This same unity exists between the different movements; a note of grief or passion sounded in the first movement is either reiterated in the last or else we feel that the composer has emerged from the struggle in triumph or noble joy. Only the minuet, an almost constant quantity with Mozart, brings a momentary relief or abandon to a lighter vein, if it is not itself, as in the G minor symphony, nobly dignified and touched with sadness.