Isleworth Mona Lisa
According to Leonardo's early biographer Giorgio Vasari, Leonardo had started to paint "Mona Lisa" in 1503, but "left it unfinished". However, a fully finished painting of a "certain Florentine lady" surfaced again in 1517, shortly before Leonardo's death and in his private possession. The latter painting almost certainly is the one that now hangs in the Louvre. Based on this contradiction, supporters of the authenticity of the "Isleworth Mona Lisa" claim it is the unfinished "Mona Lisa", made at least partially by Leonardo, and the Louvre "Mona Lisa" a later version of it, made by Leonardo for his own use.
Mona Lisa
A version of the "Mona Lisa" known as the "Isleworth Mona Lisa" and also known as the "Earlier Mona Lisa" was first bought by an English nobleman in 1778 and was rediscovered in 1913 by Hugh Blaker, an art connoisseur. The painting was presented to the media in 2012 by the Mona Lisa Foundation. It is a painting of the same subject as Leonardo da Vinci's Mona Lisa. The painting is claimed by a majority of experts to be mostly an original work of Leonardo dating from the early 16th century. Other experts, including Zöllner and Kemp, deny the attribution.