Niccolò Liburnio’s Selvette, published in Venice in 1513, is an undiscussed source for the role of art as ambiguous evidence in the early cinquecento. One of the stories in Liburnio’s book is a fictional adultery trial, in which the main evidence is a painting by Giovanni Bellini. Both the prosecutor and the defense use this painting in their arguments. No such painting by Giovanni Bellini survives (nor probably ever existed), but similar works do survive from the same period. Other paintings (Giovanni Bellini’s Nude Woman with a Mirror, Giorgione’s Laura, and Raphael’s Fornarina) do not show adulterous lovers, but do exhibit, like the image described in Liburnio’s text, a structured ambiguity, in that they could be portraits, mythological works, or allegories. This article studies how Liburnio, Bellini, and others blur the boundaries of genre in order to claim both the immediacy of realism and the license of poetic feigning.