La Belle Ferronnière is a portrait painting of a lady, by Leonardo da Vinci, in the Louvre. It is also known as Portrait of an Unknown Woman. The painting's title, applied as early as the seventeenth century, identifying the sitter as the wife or daughter of an ironmonger, was said to be discreetly alluding to a reputed mistress of Francis I of France, married to a certain Le Ferron. Later she was tentatively identified as Lucretia Crivelli, a married lady-in-waiting to Duchess Beatrice of Milan, who became another of the Duke's mistresses. Leonardo da Vinci, 1495 — painted at 43. Panel and oil paint. 63 × 45 cm. In the Department of Paintings of the Louvre. High Renaissance. Wiki link