"Like many paintings thought to be by Leonardo, controversy surrounds this picture. Some question whether it was painted by Leonardo at all. Art historians also disagree over who the subject of the portrait was. One theory suggests it shows a young lady named Cecilia Gallerani, who would have been just seventeen when when this picture was painted. Cecilia was the mistress of Ludovico Sforza - the Duke of Milan - until Ludovico settled down and married another woman. If the model was Cecilia, then the Ermine in the picture may have had a special meaning. The Greek for Ermine is Galee - a pun on the model's name. Parts of this picture have been painted over at some point in its history. The background has been darkened, and X-rays show a door has been removed. The original painting showed a woman wearing a transparent veil, but this has been retouched to look like hair. The bottom two fingers have also been altered, and look less realistic than the other two.
This painting is based on curved lines, which lead the eye. From the model's face, the gaze is drawn down the sleeve, across the back of the Ermine, and then up the other arm.The head of the Ermine in this picture is particularly lifelike. Leonardo placed emphasis on natural accuracy, and may have studied the anatomy of the creature before beginning the painting."

Leonardo Da Vinci