Leonardo da Vinci painted a younger and happier Mona Lisa some 10 years before painting the famous painting, art experts are claiming.
Slightly larger in size than the famous portrait, which now hangs in the Louvre in Paris, the painting features a darker tonality, a different and unfinished background framed by two columns, and shows a younger lady with a less enigmatic smile.
Known as the Isleworth Mona Lisa, the artwork will be unveiled in Geneva on Thursday by the Mona Lisa Foundation, a Zurich-based consortium which has kept the painting in a Swiss bank vault for 40 years.
A 320-page book will provide "historical, comparative and scientific evidence" to prove once and for all that the Isleworth work is an authentic Da Vinci artwork, a spokeman of the Swiss foundation said.
Leading Da Vinci experts Alessandro Vezzosi, the director of the Museo Ideale in the Tuscan town of Vinci, where Leonardo was born in 1452, and Carlo Pedretti of the Armand Hammer Center for Leonardo Studies at the University of California, will discuss the claim.
They have made no attribution to Da Vinci, as they believe further study is needed.
Indeed, the painting's authenticity has been the subject of debate ever since the canvas was discovered in 1913 by English art collector Hugh Blaker.
He bought it from a noble family and took it to his studio in Isleworth, London – hence the name.
In 1915 his stepfather John R. Eyre, an art historian, published a book suggesting that Leonardo painted two versions of the Mona Lisa and claiming that at least the bust, the face and the hands of the Isleworth lady were a genuine work by Leonardo Da Vinci –- basically, a prequel to his famous portrait.
Blaker then sold the painting to American collector Henry F. Pulitzer, who in turn left it to his girlfriend. On her death, it was bought by the Mona Lisa Foundation, a consortium of unnamed individuals.
Pulitzer carried out more in depth research on the painting and reinforced Eyre's theory in his 1966 book, "Where is the Mona Lisa?"
He looked into the accounts of the 16th century painter and art historian Giorgio Vasari.
In his work "Lives of the Artists," Vasari (1511–1574) named Lisa Gherardini, the wife of the wealthy Florentine silk merchant Francesco del Giocondo as the subject of the portrait and concluded that the work was painted by Leonardo between 1503 and 1506.
"Toiling on it for four years, he left it unfinished," Vasari wrote.
As Da Vinci sold a fully finished Mona Lisa to King Francis I in 1516, three years before his death, supporters of the Isleworth work argue that the painting is the unfinished Mona Lisa, partially made by Leonardo and originally handed over to the patron who had commissioned it. The Louvre masterpiece would then be a later version, made by Da Vinci for his own use.
To support the theory, Pulitzer references Giovanni Lomazzo, a biographer of artists, who in his 1584 Treatise on Painting referred to "the Gioconda, and the Mona Lisa."
Since La Gioconda is the Italian alternative name for the Mona Lisa hanging in the Louvre, Lomazzo's reference would imply that there were two distinct and separate paintings.
Pulitzer also focused on the columns which frame the Isleworth lady. Similar columns are also shown in a drawing by Raphael of the Mona Lisa. Now in the Louvre, the drawing was probably done from memory from Leonardo's original after Raphael visited the master studio in 1504.
Moreover, Vasari's description of the Mona Lisa portrait as having "a smile so pleasing" was often quoted against the Louvre picture, of which the effect has been variously described as enigmatic, mysterious and baffling.
The Isleworth picture has a real smile, it was argued.
But doubts about Vasari's attribution have persisted since he was known to rely on anecdotal evidence. The authenticity of the Isleworth Mona Lisa remained widey disputed among art historians.
"So much is wrong. The dress, the hair and background landscape. This one is also painted on canvas, which Leonardo rarely did," Martin Kemp, emeritus professor of the history of art at Oxford, told The Sunday Times.
Like the majority of Leonardo's works, the Mona Lisa in the Louvre is painted on wood.
"She might look younger but this is probably because the copyist, and I believe it is a copy done a few years after the Mona Lisa, just painted it that way," Kemp said.