Far off the beaten track in Apuglia, in the heel of the boot of Italy, lies the enchanting hill town of Martina Franca. The music festival established there in 1975 specializes in operatic rarities, scrupulously revived in the Baroque open-air courtyard of the Ducal Palace. Bellini’s Norma, some will note, is by no means the rarity it was back when only divas in a league with Callas, Sutherland, Verrett, or Caballé were entrusted with the title role. Even so, Martina Franca has a special spin in mind. For generations it has been general practice to cast a soprano as the eponymous Druid high priestess and a mezzo as the dewy acolyte Adalgisa disastrously smitten with the same Roman oppressor. This summer, the management has fielded two sopranos, a solution advertised as “undoubtedly closer to the letter and spirit of the dramaturgy envisioned by Bellini.” We’ll see. For the record, the rival Druidesses are Jacquelyn Wagner (Norma) and Valentina Farcas (Adalgisa). Fabio Luisi conducts. —Matthew Gurewitsch