Opinions have varied as to who executed the cartoon for the Portrait of Doña Isabel de Requesens, which was likely reused for that of Isabella of Aragon; Luitpold Dussler considered the painting entirely Giulio Romano's work.

[15] The subject is portrayed seated, turned to the viewer's left, wearing a deep red velvet dress trimmed with gold whose sleeves are slashed to reveal the cream fabric of her chemise, and a hat with jewels on the brim, whose shape suggests a halo.

[1] Her loose hair, the red garments (the colour of love for Petrarch), and her meeting the viewer's gaze are all sensuous details; further, the portrait is innovative in including her knees, which in addition are visibly parted, and in not having her hands chastely together as a barrier.

[17] Both Giocondae portraits feature carved cats on the right which resemble lions, a punning allusion to Leonardo.

[18] The woman in the background is replaced by a man in the portrait of Isabella of Naples; they may allude respectively to the sitter and the artist in the Mona Lisa.