Catching the ‘uncatchable smile’ illusion in Leonardo da Vinci’s La Bella Principessa Painting

In 1998 a little known painting believed to be a 19th century imitation of an Italian Renaissance painting by an unnamed German Romantic artist was sold in a New York gallery. Following examination by experts the painting was held to be a once in a lifetime discovery as it was attributed to Leonardo da Vinci! The painting is of a girl identified as Bianca, named by Kemp (2010) as “La Bella Principessa”, the illegitimate daughter of the Duke of Milan, Ludovico Sforza, who at around 13 years of age was to be married to a commander of the Duke’s Milanese forces. The portrait was commissioned by the Duke in honour of the celebration of her marriage in 1496.