"Aria del Gran Duca" (also known as "Aria di Fiorenza") is a popular melody and ground bass originating in the concluding ballet of the sixth and final intermedio by Emilio de' Cavalieri to the play La pellegrina by . The occasion for this performance on 2 May 1589 were the festivities of Ferdinando I de' Medici's marriage to Christina of Lorraine.
It spread over Europe and was used as a basis of compositions by numerous other Renaissance composers, both anonymous and named, such as Santino Garsi da Parma, Peter Philips, Sweelinck,Gasparo Zanetti, , and Adriano Banchieri. Francesca Caccini composed the song "O che nuovo stupor" as number 43 of her 1618 collection Il primo libro delle musiche using this ground bass.