Scarcely anything is known about the circumstances surrounding the composition of Mozart’s glorious Sinfonia concertante for violin and viola. In the voluminous Mozart correspondence there is no mention of any impending occasion, soloists for whom it was written, or performances that took place. The work was almost certainly completed in the summer of 1779 while Mozart was in Salzburg, having recently returned from a trip to Mannheim and Paris. No dated autograph source survives for scholarly reference, only a sketch of part of the first movement and some cadenza material. Modern editions must rely principally upon the first edition published in 1801 by Johann André.

Many have guessed that Mozart had himself in mind as the viola soloist. He had switched allegiance from the violin during this Salzburg period, much to his father Leopold’s chagrin. One can only be thankful that the circumstances did arise for Mozart to compose this glorious work, which the great Mozart scholar Alfred Einstein went so far as to call “Mozart’s crowning achievement in the field of the violin concerto.”

Though the Sinfonia concertante is scored like many earlier concertos for strings with oboes and horns, the orchestral writing is much richer. There are many passages for divided violas, extensive separation of the cello and bass parts, and the inclusion of the soloists in the many of the orchestral tuttis (ensemble sections). Furthermore, Mozart originally required the solo viola to be tuned a half-step higher than normal, to give it a brightness that made it stand out from the orchestral violas. Thus, though the work is in E-flat, the solo viola part was notated in D major. (Nowadays, however, the violist often elects to perform the solo part without this scordatura, or unusual tuning.)

Mozart’s use of the marking maestoso (majestic) was infrequent; it colors the whole sonority of the first movement. Other unusual features of this sonata form movement are the use of a long, thrilling crescendo known as a “Mannheim crescendo”—used by Mozart in the Figaro Overture but seldom elsewhere—and the eloquent semi-recitatives that open the development.

The poignant slow movement is in the older sonata form in which the second part closely follows the material of the first, except for the traditional alterations in the harmonic scheme; this framework was closer to a binary than ternary form. Each successive antiphonal phrase of the soloists seems to outdo the previous in expressiveness.

For his Presto finale Mozart employed a sonata rondo without a development—or if there is a development, it lasts only four measures after which an exact recapitulation begins. Here the soloists enter with the main theme in the subdominant, a rare device for Mozart, but one later favored by Schubert. This coupled with other unexpected events, such as the very first entrance of the soloists, contribute to an exhilarating movement rich in inventiveness.

—©Jane Vial Jaffe