This painting is a version of a picture by Cignani in the collection of the Galleria Sabauda, Turin (see B. Buscaroli Fabbri, Carlo Cignani, Cittadella 1991, p. 115, cat. no. 8).  Two canvases of the subject are noted by the artist's biographer Ippolito Zanelli as having been purchased during Cignani's sojourn in Rome (1662-5) by "due riguardevoli Personaggi," one of whom Buscaroli Fabbri identifies as the Cavaliere Gabriele Sampieri.  The Turin canvas has been tentatively identified as one of these canvases (by T. Gerevich, "Carlo Cignani," in Thieme Becker Allgemeines Lexikon der Bildenden Künstler, Leipzig, 1912, vol. VI, p. 576, who mentions another painting of the subject in Vienna).  Stylistically this would make sense as a dating for the present composition as well, which differs in slight details from the Turin canvas, most noticeably in the inclusion of a tendril of hair falling over the goddess's right breast.