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.
Speculations about Mona Lisa
In December 2010, Italian art historian Silvano Vinceti reported that the Mona Lisa appears to have tiny letters and numbers in her eyes which are only apparent when viewed with a magnifying glass and shortly afterwards said that the model was Leonardo's male apprentice Gian Giacomo Caprotti (known as Salaì) and that the letters were clues to his identity. The Louvre, pointing out that he had had no access to the actual painting, said that after "every laboratory test possible" in 2004 and 2009 that "no inscriptions, letters or numbers, were discovered during the tests." and that "The ageing of the painting on wood has caused a great number of cracks to appear in the paint, which have caused a number of shapes to appear that have often been subject to over-interpretation".