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.
Vincenzo Peruggia
In 1911, Peruggia perpetrated what has been described as the greatest art theft of the 20th century. It was a police theory that the former Louvre worker hid inside the museum on Sunday, August 20, knowing the museum would be closed the following day. But, according to Peruggia's interrogation in Florence after his arrest, he entered the museum on Monday, August 21 around 7 am, through the door where the other Louvre workers were entering. He said he wore one of the white smocks that museum employees customarily wore and was indistinguishable from the other workers. When the Salon Carré, where the "Mona Lisa" hung, was empty, he lifted the painting off the four iron pegs that secured it to the wall and took it to a nearby service staircase. There, he removed the protective case and frame. Some people report that he concealed the painting (which Leonardo painted on wood) under his smock. But Peruggia was only , and the "Mona Lisa" measures approx. , so it would not fit under a smock worn by someone his size. Instead, he said he took off his smock and wrapped it around the painting, tucked it under his arm, and left the Louvre through the same door he had entered.