The identity of the Mona Lisa, which hangs in the Louvre in Paris and draws 8.5 million visitors a year, has been an enduring mystery.
But now her (or is it his?) secrets are seemingly being revealed every few years.
A group of Italian scientists and art historians announced today that a male apprentice and longtime companion of da Vinci was the main influence and model for the "Mona Lisa" painting, The Associated Press reported.
Two years ago, however, researchers at Germany's Heidelberg University announced that they had cracked the secret of Mona Lisa's identity beyond "all doubts," Reuters reported at the time.
They said the model for the 16th-century portrait was, as long-rumored, Lisa Gherardini, the wife of a wealthy Florentine merchant, Francesco del Giocondo.
But the Italian researchers, while not entirely ruling out Lisa Gherardini, believe the bigger influence for the painting was an apprentice named Gian Giacomo Caprotti, known as Salai. He worked with da Vinci for 20 years beginning in 1490. Their relationship has been described as ambiguous.
"Salai was a favorite model for Leonardo," researcher Silvano Vinceti told the AP. "Leonardo certainly inserted characteristics of Salai in the last version of Mona Lisa."
But Vinceti agreed that the famous portrait may have been inspired by more than one influence.
"The 'Mona Lisa' must be read at various levels, not just as a portrait," Vinceti said.
To confuse matters, da Vinci expert Pietro Marani called the theory "groundless."
Read more of The Associated Press story here.