The sonatas of Bach and Mozart for “harpsichord with an accompaniment for a violin,” as eighteenth-century composers entitled them, reversing the procedure customary in our time, are actually, of course, works of chamber music in which all the instrumental parts assume equal importance, unlike the contemporary works in which the keyboard player merely improvised an accompaniment on a figured bass. These sonatas are well known in the literature for violin and piano, but opportunities to hear them in the form in which they were originally conceived have been rare.

Mozart, as is known, composed his most important keyboard music at the moment when the harpsichord was about to be replaced by another instrument, the pianoforte—not the pianoforte of our day, but an instrument as remote from it as the harpsichord, and in quality of tone and in style of playing much closer to the harpsichord. It is an instrument which deserves to be revived, for the subsequent progress of piano building has been attended with loss as well as gain. In Mozart's time, even long after he himself was playing pianofortes when they were available, the harpsichord was still the keyboard instrument most widely prevalent. The differences between the two were still not great enough to preclude the use of either instrument interchangeably. Thus we find thirteen out of the sixteen best-known violin sonatas of Mozart first published as “Sonatas for the Harpsichord or Pianoforte with the Accompaniment of a Violin.” Only one (K. 526) mentions the pianoforte before the harpsichord, and the other two are without designation.

This should not be interpreted as evidence for an attempt to claim Mozart sonatas for the harpsichord alone, for his own use of the pianoforte is well known, but it indicates that the alternative use of the harpsichord was envisaged, and in our day, until the reconstruction of a good Mozart piano, the advantages of the harpsichord over the modern piano as a companion of stringed instruments makes its use in the majority of the violin sonatas vastly preferable. With the harpsichord, as with the early pianos, it is possible to achieve easily and naturally a blend of tone with the violin, to color and to orchestrate without danger of forcing and loss of clarity.