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 (opera)
In the spring of 1913, Beatrice von Dovsky presented the libretto to the composer, who prepared a piano sketch during the following summer. He completed the opera during his eight-month military duty as a medical soldier in France and Belgium. The subject was very topical at the time, because the painting by Leonardo da Vinci had been stolen from the Louvre in 1911, and rediscovered in Florence in 1913.