Lost Masterpieces

At a private farewell gathering on the eve of Leonardo da Vinci's departure for Milan to enter the service of Duke Ludovico Sforza, three of Italy's greatest masters--Sandro Botticelli, Titian, and Andrea Mantegna--honored him with personal gifts: small paintings, each carrying a hidden message known only to artist and recipient.Botticelli, the poet of grace and spiritual beauty, presented a delic...