Where did the “Mona Lisa” smile?

For centuries, two of the most intriguing questions about Leonardo da Vinci’s “Mona Lisa” were “Who?” and “When?” A discovery made at Heidelberg University in 2005 pretty much answered both. A note written in a manuscript in the library confirmed the account of da Vinci’s first biographer, Giorgio Vasari: that the sitter was a merchant’s wife, Lisa Gherardini. The note also helped date the masterpiece to between 1503 and 1506.

A third conundrum—“Where?”—is still in dispute. But on June 3rd a French engineer, Pascal Cotte, declared that he and a collaborator had identified the landscape in the background of the painting. Arguments had previously been made for stretches of countryside in the Marche region and between Milan and Genoa. During a presentation in Vinci, near Florence, Mr Cotte contended that the artist was more plausibly depicting a part of his native Tuscany—one that keenly interested him at the time. According to this theory, da Vinci represented the area not as it was, but as, in an unrealised scheme, he intended it to be.