The Mona Lisa is arguably one of the most iconic pieces of art to have ever been created by anyone. The mystery and the myth surrounding the work has elevated it to a level that goes beyond that achieved by any other piece.
Almost every facet of the painting's existence has been hotly debated by experts and analysts, including the subject of the painting itself.
The most popular explanation is that the subject of the painting is the wife of a merchant from Florence.
However, an Italian art detective claims that Lisa Gherardini may only have offered one half of the inspiration behind the famous piece.
Silvano Vinceti said that the Mona Lisa is an “androgynous” amalgam of Gherardini, and Gian Giacomo Caprotti, better known by his nickname, Salai.
“The Mona Lisa is androgynous – half man and half woman. The painting was based on two models. The first was Lisa Gherardini and the second was Salai, Leonardo’s apprentice,” Mr Vinceti told The Telegraph.
Believed to be Da Vinci's male apprentice, Vinceti claims that Salai was also likely to be his gay lover.
Caprotti is thought to have been a part of Leonardo’s life around 1490, at which point he was about 10 years old. Having worked as the seminal artist's assistant for the next 20 years, he acquired the the nickname Salai, or Little Devil.
Vinceti, the head of a research group called the National Committee for Cultural Heritage, has based his findings on infra-red examination of the Mona Lisa, adding that he found the subject's nose, forehead and smile to be strikingly similar to paintings created by Da Vinci that used Salai as a model.
These other pieces include portraits of St John the Baptist and St Anne and an erotic drawing, The Incarnate Angel, which depicts a young man with an erection.
“We’ve come up with an answer to a question that has divided scholars for years – who was the Mona Lisa based on,” he added.
However, the Italian's claims have been met with scepticism by some experts.
Martin Kemp, professor emeritus of the history of art at Trinity College, Oxford, dismissed the idea as a "mish-mash of known things, semi-known things and complete fantasy".
“The infra-red images do nothing to support the idea that Leonardo somehow painted a blend of Lisa Gherardini and Salai," he added.
Professor Kemp also suggested there was not enough information available about what Salai looked like, meaning it was almost impossible to know whether his features were incorporated into the piece.