Concerto for Violin and Cello in F major, "Il Proteo, o sia il Mondo al rovescio" RV 544

Among the dozens of concertos Vivaldi wrote pairing two solo instruments, RV 544 is the one with the wink. The full title — Il Proteo, o sia il Mondo al rovescio ("Proteus, or the World Upside Down") — points at the joke. Proteus, the shape-shifting sea-god of Greek myth, refuses to stay put; here, neither do the soloists. The violin spends a surprising amount of time in cello territory, the cello climbs into violin range, and the parts are written so cleverly that, with the right transposition, the two players could simply trade scores. It's a piece that rewards a soloist willing to play the trick straight. The opening Allegro lays out a clean F-major ritornello that sets the rules of the game before the soloists start bending them — answering each other's phrases, doubling at the unison or octave, then diverging just when the ear expects symmetry. The Largo drops the orchestra back and lets the violin and cello sing in long, intertwined lines over continuo, more aria than concerto slow movement. The closing Allegro is the most overt about the conceit, with passages that look idiomatic for one instrument quietly handed to the other. For the cellist, the high tessitura and sustained dialogue with the violin ask for a sound that can match a soloist a fifth higher without thinning out. It's a work that wants character more than display, which is, of course, exactly why it's worth playing.