RV420 begins strikingly with a solo accompanied only by continuo that precedes the first ritornello (this term denotes an orchestral refrain). Such openings, though relatively uncommon, remained an option for Vivaldi throughout his career; the best-known comparable instance is the cadenza-like opening of the D minor concerto Op 3 No 11 (RV565). Its slow movement, dominated by an orchestral theme in fiercely jagged rhythm, is in a miniature version of the ritornello form normally employed for the fast outer movements. A noteworthy feature of the tempestuous finale is that it has five, rather than the more usual four, ritornellos.
from notes by Michael Talbot © 2006