A GERMAN art historian claims to have solved one of the greatest mysteries of the Renaissance by discovering the identity of Mona Lisa. Magdalena Soest, 56, from Leverkusen in Germany, believes that Leonardo da Vinci based his famous portrait on a young, adventurous beauty called Caterina Sforza. Frau Soest believes that Leonardo based his painting, produced between 1500 and 1506, on a portrait of Sforza, the Duchess of Forlì and Imola, that was painted by the Italian master Lorenzo di Credi. “I wholeheartedly believe that she is one and the same person,” Frau Soest, a respected artist and consultant to...