Mona Lisa
The painting is thought to be a portrait of Lisa Gherardini, the wife of Francesco del Giocondo, and is in oil on a white Lombardy poplar panel. It had been believed to have been painted between 1503 and 1506; however, Leonardo may have continued working on it as late as 1517. Recent academic work suggests that it would not have been started before 1513. It was acquired by King Francis I of France and is now the property of the French Republic, on permanent display at the Louvre Museum in Paris since 1797.
Speculations about Mona Lisa
German imaging researchers Claus-Christian Carbon of the University of Bamberg and Vera Hesslinger of the University of Mainz performed further analysis of the Museo del Prado version, comparing it to Da Vinci's "Mona Lisa", and in May 2014 speculated that, based on perspective analysis of key features in the images, the two images were painted at the same time from slightly different viewpoints. They further proposed that two images may therefore form a stereoscopic pair, creating the illusion of 3-dimensional depth, when viewed side by side. However, a study published in 2017 has demonstrated that this stereoscopic pair in fact gives no reliable stereoscopic depth.