When this Concerto in A minor was written no one knows. But it was published in 1711 as the sixth in a set of 12 for one or more solo string instruments, with the collective title L'estro armonico, Op. 3. The original scoring was for solo violin, small string orchestra, and continuo.
During the composer's largely mysterious lifetime -- he left no correspondence, and few descriptions of him survive -- the popularity of L'estro armonico (Harmonic Fire or Inspiration) was rivaled only by The Four Seasons, from his Op. 8 collection, The Wedding of Harmony and Invention, published 14 years later. L'estro armonico had widespread impact on Vivaldi's audiences as well as colleagues, yet it is not thought to represent his solo virtuosity. He well may have been the Paganini of his age, minus the diablerie that nineteenth-century audiences imputed to artists with larger-than-life talent.
At the Pio Ospedale della Pietà, one of four music-school orphanages in Venice for girls, Vivaldi taught music and conducted a chorus irregularly between 1703 and 1736, but never full time. Composing and performing were his chief occupations. Venice was no longer a mercantile and maritime hub by the seventeenth century; it had become what it is today -- a tourist attraction, celebrated for the arts. Concerts at the Pietà produced significant endowments as well as ticket revenue, and Vivaldi the composer/violinist remained box-office for years. On the side, and not without double-dealing, he did a thriving business in manuscript copies -- cheaper, quicker, and cleaner to produce than printing, until Amsterdam publishers achieved a technical breakthrough ca. 1711. Even then, beginning with L'estro armonico, Vivaldi permitted the publication of only 86 concertos in his lifetime out of hundreds discovered since 1927. And these are not the sum of his output. As with Bach and other Baroque luminaries, we know that music was lost; but how much will never be known.
This concerto (even if Bach passed on it in favor of others to arrange, and Stravinsky sneered that Vivaldi wrote the same concerto 500 times) is a choice specimen of his gift for sheer invention. The first movement is a vivid example of the ritornello technique he perfected -- repeating a theme between flights of decoration and elaboration, looking forward to the rondo.
One may note, too, that the solo violin refuses to play the theme as we hear it in tutti passages, and that concertino passages are nudging structure toward the development-group principle. What follows, in Alfred Einstein's view, is "a tender Intermezzo, raised to the regions of a more spiritual passion. Three violins and a viola accompany the lyrical rhetoric of the solo [instrument], and the second violins (long held notes over the solo part) give a soft glow to the whole movement. Thematically, rhythmically and dynamically, the last movement is a pure Capriccio, a form typical for finales [of the period]."