Italian Paintings of the Sixteenth Century: Irene di Spilimbergo, c. 1560 | National Gallery of Art https://www.nga.gov/research/publications/italian-paintings-sixteenth-century-0/italian-paintings-sixteenth-century-irene-di-spilimbergo-c-1560
contemporaneously as pendants, the motif probably alludes to the turbulent state of her emotions