The Vivaldi recordings by Adrian Chandler and his British period instrument ensemble La Serenissima, named after the nickname of the Venetian Republic and specializing in its music, are breaking new ground. Give this one a try if you haven't heard the group before: it's wonderful. Chandler focuses on double concertos, which Vivaldi produced in profusion for his players as the Osepale della Pietà, but which have been largely neglected on recordings.