Quotes of the Day

That smile: No, we still don't know why. But one expert claims to have solved the question of where.

For centuries the enigmatic smile of Leonardo Da Vinci's 500-year old masterpiece, the Mona Lisa, has intrigued, infatuated and even befuddled academics.  But now Italian art historian Carla Glori claims to have solved a real life Da Vinci Code mystery of the landscape in the painting, reports the Guardian.

She argues that the three-arched stone bridge over the Mona Lisa's left shoulder is in Bobbio, Piacenza, in northern Italy.

Her theory is based on a 2010 discovery, in which art historian Silvano Vinceti unveiled the numbers 7 and 2 concealed in the bridge. Most art historians believe the background, which features valleys and mountains, is an idealized landscape drawn from Da Vinci's imagination.

But Glori is now convinced that it depicts a specific place with 7 and 2 referring to 1472, when the Bobbio bridge was almost destroyed by flooding before being rebuilt. She came to this conclusion while investigating the possibility that Bianca Giovanna Sforza, the daughter of Ludovico Sforza, the 15th century duke of Milan, sat for Da Vinci, and not Lisa del Giocondo in Florence, as is widely believed. 

But fellow art historians disagree."There is no Dan Brown code here, just messages that reveal his thinking,"  said Silvano Vinceti. "Both the numbers seven and two are very important in the Kabbalism."

Vinceti's team are also studying candidates from the court of Ludovico as possible sitters for the Mona Lisa. "But we believe Bianca Giovanna Sforza is unlikely because she died at 15 and the sitter is at least 22," he said. Glori said she believed Da Vinci may have aged Sforza's face over the years he spent finishing the painting in a bid to hide her identity following her father's downfall.

Martin Kemp, a renowned Da Vinci scholar, also said that he was not convinced. "The portrait is almost certainly of Lisa del Giocondo, however unromantic and un-mysterious that idea might be," he said, adding that he also had his doubts on Bobbio. "Leonardo is remaking an archetypal landscape on the basis of his knowledge of the 'body of the earth'." ((See the Top 10 Brazen Heists)

Glori will publish further details in her new book, The Leonardo Enigma, which comes out later this year.

• TARA KELLY