Concerti Con Organo Obligato
Among Vivaldi's 600 or so concertos, those for keyboard - organ or harpsichord are surprisingly small in number for this most prolific of baroque composers. Of these works, nine in all, there are also several rather tantalizing fragments and odd movements, and all betray in the keyboard writing, the composer's genius as a violinist. The right hand plays violinistic figurations, whilst the left more often than not plays a simple bass line. Interestingly, many of these concertos are arrangements by Vivaldi of concertos for other forces with the exception of RV541 and 542 - both composed as violin and organ concertos. The 2nd movement of RV541 is especially effective with the organ accompanying the violin with a discreet bass line and three-note chords on the right hand. Vivaldi calls for an improvised cadenza in the finale.