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
The "Mona Lisa" has had many different decorative frames in its history, owing to changes in taste over the centuries. In 1909, the Comtesse de Béhague gave the portrait its current frame, a Renaissance-era work consistent with the historical period of the "Mona Lisa". The edges of the painting have been trimmed at least once in its history to fit the picture into various frames, but no part of the original paint layer has been trimmed.