Da Vinci placed an ermine in the portrait alongside Cecilia, which served as an allegory of purity, innocence, and restraint in Renaissance art.

The ermine was also associated with chivalric culture and was sometimes depicted in medals. The image of the ermine was also placed on items of wedding equipment for Italian brides, suggesting that the portrait may have been part of her betrothal equipment (the period of the painting's creation is connected with the wedding of Cecilia to the Duke of Bergamo).