Who is the Mona Lisa? This question prompts a thriller-like quest across Europe, in search for clues about the identity of the lady in the Louvre. She is not, Lisa del Giocondo, the wife of a Florentine silk merchant as previously thought because a newly discovered document shows that if Leonardo did paint Lisa, he must have done it in 1503—at least 10 years before the dating of the Mona Lisa in the Louvre.