From Reuters:
Lisa Gherardini, the wife of a wealthy Florentine merchant,
Francesco del Giocondo, has long been seen as the most likely
model for the sixteenth-century painting.
But art historians have often wondered whether the smiling
woman may actually have been da Vinci's lover, his mother or
the artist himself.
Now experts at the Heidelberg University library say dated
notes scribbled in the margins of a book by its owner in
October 1503 confirm once and for all that Lisa del Giocondo
was indeed the model for one of the most famous portraits in
the world.
"All doubts about the identity of the Mona Lisa have been
eliminated by a discovery by Dr. Armin Schlechter," a
manuscript expert, the library said in a statement on Monday.
Until then, only "scant evidence" from sixteenth-century
documents had been available. "This left lots of room for
interpretation and there were many different identities put
forward," the library said.