Researchers claim proof for second Mona Lisa, but doubts persist

A Swiss-based foundation said it will present proof on Thursday that Leonardo da Vinci painted an earlier version of the Mona Lisa.

The Mona Lisa Foundation said it has "historical, comparative and scientific evidence" that the Isleworth Mona Lisa, as the painting is known, is indeed another portrait of the same woman, which predates the famed 16th century portrait by some 12 years.

Art historians have known of the painting's existence since shortly before World War I, but many experts have judged it to be a later copy and some have questioned whether the Italian master even painted it.

Several art historians remained skeptical, despite the foundation citing studies ahead of its announcement that indicate close geometric similarities between the works.

"There is no foundation for it at all," British da Vinci scholar Martin Kemp told dpa, citing differences in the way the hair, hands, dress and background are painted.