La stravanganza ("The Extraordinary") is a set of concertos, op. 4, written by Antonio Vivaldi in 1712-1713. The set was first published in 1714 and was dedicated to a Venetian nobleman Signor Vettor Delfino. All of the concertos were scored for solo violin, strings, and basso continuo; however, some of the movements in the concertos require extra soloists (like a second violin solo and/or a cello solo). What is perhaps most extraordinary about "La stravaganza" is Vivaldi's remarkable inventiveness within a defined framework of instrumental and harmonic forces. - wiki