Milan museum to test whether sketch is lost Leonardo da Vinci work

Peter Hohenstatt was skeptical at first, especially when he learned the drawing dated to about 1500.

The sketch was "absolutely Leonardesque," the University of Parma art historian thought, but it was probably the product of one of the master's students, imitators or admirers. When a technical exam showed the drawing originated closer to 1473, his skepticism waned.

The reason? Leonardo da Vinci was an apprentice until the late 1470s. He didn't have any students, imitators or admirers of his own yet. 

The object of their fascination is titled simply, "red pencil drawing of a profile of a man's head looking to the left." It was found about 70 years ago tucked into a book -- and like many objects of artistic intrigue, it has a long and twisting story, regardless of whether it's the product of the Renaissance master.

The two men's convictions are based on artistic similarities to other da Vinci works as well as the makeup of the sketch's paper, which they say is similar to the paper da Vinci used in other sketches.

The final word, though, must come from the Biblioteca Ambrosiana, the library in Milan, Italy, that houses the Codex Atlanticus, the largest collection of da Vinci's works.....