That Leonardo painted such a work, and its date, were confirmed in 2005 when a scholar at Heidelberg University discovered a marginal note in a 1477 printing of a volume by ancient Roman philosopher Cicero. Dated 1503, it states that Leonardo was working on a portrait of Lisa del Giocondo. Leonardo's assistant Salaì, at his death in 1524, owned a portrait which in his personal papers was named la Gioconda, a painting bequeathed to him by Leonardo.Ī margin note by Agostino Vespucci (visible at right) discovered in a book at Heidelberg University. It has long been the best-known source of information on the provenance of the work and identity of the sitter. Vasari's account of the Mona Lisa comes from his biography of Leonardo published in 1550, 31 years after the artist's death. The title of the painting, though traditionally spelled Mona in English, is spelled in Italian as Monna Lisa ( mona being a vulgarity in Italian), but this is rare in English. This became madonna, and its contraction monna. It comes from a description by Renaissance art historian Giorgio Vasari, who wrote "Leonardo undertook to paint, for Francesco del Giocondo, the portrait of Mona Lisa, his wife." Monna in Italian is a polite form of address originating as ma donna – similar to Ma'am, Madam, or my lady in English. The title of the painting, which is known in English as Mona Lisa, is based on the Lisa del Giocondo Theory. It holds the Guinness World Record for the highest known painting insurance valuation in history at US$100 million in 1962 (equivalent to $870 million in 2021). The Mona Lisa is one of the most valuable paintings in the world. It has been on permanent display at the Louvre in Paris since 1797. It was acquired by King Francis I of France and is now the property of the French Republic. It had been believed to have been painted between 15 however, Leonardo may have continued working on it as late as 1517. Leonardo never gave the painting to the Giocondo family, and later it is believed he left it in his will to his favored apprentice Salaì. It is painted in oil on a white Lombardy poplar panel. The painting has been definitively identified to depict Italian noblewoman Lisa Gherardini, the wife of Francesco del Giocondo. The painting's novel qualities include the subject's enigmatic expression, the monumentality of the composition, the subtle modelling of forms, and the atmospheric illusionism. Considered an archetypal masterpiece of the Italian Renaissance, it has been described as "the best known, the most visited, the most written about, the most sung about, the most parodied work of art in the world". The Mona Lisa ( / ˌ m oʊ n ə ˈ l iː s ə/ Italian: Gioconda or Monna Lisa French: Joconde ) is a half-length portrait painting by Italian artist Leonardo da Vinci. The Mona Lisa digitally retouched to reduce the effects of aging.