ABSTRACT
This chapter discusses briefly J.S. Bach's approach to ritornello form in terms of system analysis, an approach remarkably similar to that of Antonio Vivaldi and his Italian contemporaries. During the first half of the seventeenth century, a period in which the confrontation of modality and tonality is at its most extreme, the listener is often presented with modal-tonal passages that constantly fluctuate between minor and major triads and often leave the tonic itself in doubt. It is generally acknowledged that Vivaldi brought the Italian concerto to its height; his numerous and inventive concertos display practically every conceivable permutation of the ritornello form that he helped to establish. Vivaldi's opening ritornello is orchestrated for unison strings, in a typical opening gambit of many Venetian concertos of the early eighteenth century. In the vast number of concertos composed in the major mode during this period, the penultimate ritornello statement before the return of the tonic was often the minor mediant.
