A lost painting by Leonardo da Vinci described by a monk in 1501

The Carmelite monk Fra Pietro da Novellara wrote a letter to Isabella d'Este on April 3, 1501, describing the only cartoon by Leonardo da Vinci then visible in Florence. This precious document allows us to know the lost work, where the Child Jesus tries to seize a lamb while his mother tries to separate him from it. The text also specifies that the arrangement of the characters was reversed compared to the final painting kept at the Louvre Museum.