German academics claimed that they've solved the mystery behind the identity of Mona Lisa

For centuries, her smile is fascinated and intrigued. And the real identity of the "Mona Lisa" --a Leonardo da Vinci's famous painting, has also been a mystery. As art historians have wondered whether she could have even been the artist's mother, or his lover.

But German academics at the University of Heidelberg say they have cracked the code, Armin Schlechter, a manuscript expert, discovered some notes scribbled in the margin of this book that once belonged to an acquaintance of da Vinci. These notes were made in an edition of letters by Cicero in October 1503, and say the artist was working on three paintings at the time, including a portrait of Lisa del Giocondo.

"This is the earliest mention of the fact that Leonardo da Vinci painted a picture which portrays a certain woman called Lisa del Giocondo. People have guessed that he was working on this picture in 1503."

The suggestion that Lisa Gherardini, the wife of Francesco del Giocondo, a wealthy merchant from Florence, could be the smiling woman is nothing new. The painting, which hangs in the Louvre in Paris, is also known as "La Gioconda" which refers to her name but also means happy, or smiling, woman in Italian. Art experts, who have already dated the painting to the start of the sixteenth century, have described the Heidelberg discovery as a breakthrough. Schlechter actually found the notes two years ago and although they were printed in Heidelberg library's public catalogue, they hadn't received much attention until recently. But while the Mona Lisa's identity may have been solved, the mystery behind that smile is unlikely to be cracked any time soon.

Joanna Partridge, Reuters.