GENEVA (Reuters) - A younger vision of Leonardo da Vinci's "Mona Lisa" will be presented in Geneva on Thursday with the suggestion that it is the original version of what has been called the world's most famous painting.
The Swiss-based Mona Lisa Foundation organising the event said on Wednesday that detailed research over three decades strongly indicates that it is an earlier portrayal by the Italian genius of "the lady with the mystic smile."
"We have investigated this painting from every relevant angle and the accumulated information all points to it being an earlier version of the Giaconda in the Louvre," foundation member and art historian Stanley Feldman, told Reuters.
In Italy and France, the one currently recognised Leonardo "Mona Lisa" is known as "La Giaconda" or "La Joconde" after Lisa Gherardini, wife of early 16th century Italian nobleman Francesco del Giacondo who commissioned a portrait of her.
But Leonardo never delivered it to him.
The portrait to be presented to experts and media in Geneva shows a woman appearing to be in her early 20s -- rather than the early 30s of the Louvre painting -- in the same pose and with much the same enigmatic stare as the Louvre masterpiece.
The Irish-born Feldman and his brother David, long involved in the art world, said historical evidence, critical comparison and scientific examination using the most modern techniques supported their view on what it really is.
Cautiously backing the "two versions" thesis -- which if proven would create a major sensation in the art world -- are leading Italian Leonardo specialist Alessandro Vezzosi, another foundation member, and U.S.-based expert Carlo Pedretti.
But other experts on the artist, sculptor, architect and designer who bestrode the European cultural world from the late 15th century until his death in a small French chateau on the Loire at the age of 67 in 1519, are strongly sceptical.
In a luxuriously produced 300-page illustrated volume to be issued by the foundation on Thursday, Vezzosi, director of the Leonardo museum in the artist's home town of Vinci in central Italy, calls on the critics to keep an open mind.
The book, "Mona Lisa-Leonardo's Earlier Version", "will permit an unbiased judgement of the claim of this painting to be the earlier portrait, incomplete, of a young Mona Lisa, much younger than that of the Louvre," Vezzosi writes.
But in comments printed last weekend in a London newspaper, Oxford University professor Martin Kemp argued that the Geneva portrait is probably a copy of the Paris version by an unknown painter who simply chose to make the subject younger.
"So much is wrong," said Kemp, a world-recognised authority on Leonardo, pointing to the fact ---- among others -- that the foundation's portrait is painted on canvas and not on wood, the artist's preferred medium.
The "younger version" -- which the Feldmans think was probably painted around 1505 -- is not new to the art world, though -- apart from a brief excursion to Japan -- it has been in a Swiss vault for many years.
It was discovered in 1913 by collector Hugh Blaker -- who had already made several art discoveries -- in a manor house in the west of England where it had hung for a century unnoticed. How it got there is unknown.
Blaker took it to his home in a London suburb, where it was dubbed "the Isleworth Mona Lisa." On his death in 1936, it was bought by American collector Henry Pulitzer, who deposited it in a Swiss bank while writing a book about it, published in 1972.
When Pulitzer died in 1979, it passed to his Swiss business partner, and on her death in 2010, it was bought by an international consortium, its current owners.
The Louvre "Mona Lisa", which draws huge crowds daily, was in Leonardo's possession when he died in France. It then found its way into the collection of King Francois I, but exactly how it got there has never been established.
Reporting by Robert Evans, editing by Paul Casciato