The "concerto for strings," without soloists, was actually the original form of the genre now called concerto, originating in the late 17th century. Vivaldi was one of the few composers to write them during the High Baroque era. Their purpose, as with so much of Vivaldi's music, is not known, but a reasonable guess is that he wrote them for the orchestra at the Ospedale della Pietà, the home for the illegitimate children of the aristocracy where he worked for much of his career. That supposition would fit with the highly innovative, almost experimental quality of many of these works, which on one hand break up the basic homogeneous Baroque texture with sharp motivic contrasts, and on the other make greater use of the fugue than most all of Vivaldi's other works. They're curious pieces with an almost abstract quality that sets them apart from the basically operatic language of most of Vivaldi's other music. The spiky sound of the Polish historical-instrument group
Arte dei Suonatori is ideal here, with plenty of gutsy texture in the string sound deployed with unfailing musical intelligence and a bit edgily rendered by BIS engineers, rendered in a seminary church in Poland. The booklet lists a leader, Aureliusz Golinski, but no conductor, and the playing has the rare feel of an ensemble whose players are truly interacting with each other rather than following someone's lead. Highly recommended.