Parrull, New Delhi: The art world's most enduring riddle has finally been solved as German art historians claim they know who the Mona Lisa is supposed to be.

Since centuries, the Louvre crowd-puller has faced tremendous scrutiny and speculation, spawning reams and reams of theories on her identity, ranging from an Italian merchant’s wife to an amused and androgynous self-portrait of Leonardo da Vinci himself, to a lover or mother of the artist.

Now, German academics claim they have finally solved the riddle and going by notes scribbled in the margins of a book by its owner back in October 1503, they have confirmed that Mona Lisa was none other than Lisa del Giocondo, a Florentine merchant's wife.

"There were many speculations and essays on the question you Mona Lisa might be. The craziest version was that it is Leonardo da Vinci himself, portraying himself with this magic smile in an ironic and playful way," said historian and manuscript expert Armin Schletchter.

Art experts describe the Heidelberg discovery as a breakthrough and the earliest mention linking the merchant's wife to the portrait.

The notes were made by a Florentine city official who was an acquaintance of the artist. He made them in a collection of letters by the Roman orator Cicero.

The comments compare da Vinci to the ancient Greek artist Apelles and say he was working on three paintings at the time, one of them a portrait of Lisa del Giocondo.

"This is the oldest mention of the fact that Leonardo da Vinci did a painting showing one Lisa del Giocondo," explained Schlechter. "It was assumed that he worked on the painting in 1503. The assignment of the painting, or rather, the identification of the person on the painting as Lisa del Giocondo as Mona Lisa happened much later, decades later."