[Grim]

Art historians believe Leonardo might have kept the painting for himself because it touched him on some personal level, but no one's quite sure.

Could be simply that the banker who comissioned the portrait didn't pay up so the work was never delivered.

[shineon]

That's highly unlikely. Leonardo was really a hobo. This train of thought lends it's self quite nicely to documenting all sorts of invaluable and prehistoric passages inside and outside of scripture, not the least of which, well known to the scholars of that period included a precise yet hidden description of the Council of Worms.

There is quite a bit of evidence that x-rays of Leonardo himself prove that he knew little of the cinematic techniques employed in this movie.