Mona Lisa
Today the "Mona Lisa" is considered the most famous painting in the world, but until the 20th century it was simply one among many highly regarded artworks.
Once part of King Francis I of France's collection, the "Mona Lisa" was among the first artworks to be exhibited in Louvre, which became a national museum after the French Revolution. From the 19th century Leonardo began to be revered as a genius and the painting's popularity grew from the mid-19th century when French intelligentsia developed a theme that it was mysterious and a representation of the femme fatale.
The Baedeker guide in 1878 called it "the most celebrated work of Leonardo in the Louvre", but the painting was known more by the intelligentsia than the general public.
The 1911 theft of the "Mona Lisa" and its subsequent return was reported worldwide, leading to a massive increase in public recognition of the painting. During the 20th century it was an object for mass reproduction, merchandising, lampooning and speculation, and was claimed to have been reproduced in "300 paintings and 2,000 advertisements". It has been said that the "Mona Lisa" was regarded as "just another Leonardo until early last century, when the scandal of the painting's theft from the Louvre and subsequent return kept a spotlight on it over several years."
Isleworth Mona Lisa
In October 2013 Jean Pierre Isbouts published a book titled "The Mona Lisa Myth" examining the history and events behind the Louvre and Isleworth paintings and confirmed the latter's attribution to Leonardo. A companion film was released in March 2014. In April 2014, Albert Sauteur examined the perspective used to execute the "Isleworth Mona Lisa" and the "Mona Lisa" in the Louvre, and concluded that Leonardo painted both works. In July 2014 "The Mona Lisa Mystery" premiered on the PBS television station's series "Secrets of the Dead". This documentary investigated, at length, the authenticity of the Isleworth painting.