The identity, the client and the dating of the Mona Lisa are still widely debated.

The most feasible hypotheses, however, link the painting to Florence. It is thought to be a portrait of Monna Lisa Gherardini, in which André Chastel recognises the Mona Lisa recalled by Vasari's legend. According to Vasari, in fact, the portrait was painted for Francesco del Giocondo, between 1502 and 1506, remaining unfinished. Instead, based on what Leonardo himself told Cardinal d’Aragona, showing him the painting in his residence of Cloux (Clos Lucé) at Amboise, the painting portrays a «certain Florentine woman, done from life and at the request of the so-called Magnificent Juliano de Medici». In this case, it would be the portrait of a favourite of Giuliano de’ Medici, which, based on element of style, would be datable to the years around 1514, when Leonardo was a member of Giuliano's entourage in Rome and Florence.

If we accept Chastel's hypothesis, we should thus recognise the Mona Lisa as a portrait of Lisa Gherardini, born in Florence, in Via Maggio, in 1479. Her family owned farms they rented out at Panzano in Chianti (Ca’ di Pesa) and San Donato in Poggio (Cortine, Selvaramole and San Silvestro) as well as a villa at Vignamaggio, sold later due to financial problems. The San Silvestro farm instead was the dowry accorded Lisa when she married the silk merchant Francesco di Bartolomeo del Giocondo in 1495.

Five children were born of this marriage; of the eldest, born in 1496, Leonardo painted the portrait "from life", according to the testimony of the Anonymous Gaddiano. In 1502 the third child, Andrea, was born and this event could have been a justifiable occasion for having a portrait of his mother painted.

Based on documents published by Giuseppe Pallanti, and others by Josephin Rogers Mariotti, we know that Lisa Gherardini was left a widow in 1538. She spent her last years in the Florentine Convent of Sant’Orsola, where she died on July 15, 1542 and was buried (rather than in the family tomb of her husband at Santissima Annunziata). This definitively refutes another tradition according to which she died and was buried at Lagonegro, in Basilicata.

As regards instead the hypothesis that Mona Lisa was a favourite of Giuliano de’ Medici, the most probable identification would be that of Isabella Gualanda. This theory however is not fully convincing, since she came from a Tuscan family, but from Pisa and not Florence. Isabella was born around 1491 in Naples (which would explain the fact that Lomazzo referred to the woman in the portrait as "Mona Lisa, Neapolitan"). Her father was the Ranieri Gualandi from Pisa and her mother Bianca Gallerani, a cousin of that Cecilia portrayed by Leonardo in the Lady with an Ermine.

Left a widow (and this would explain the black veil worn by the Mona Lisa) in 1514, she could have been in Rome, in the circle of Vittoria Colonna and beloved by Giuliano de’ Medici, a year before he married Filiberta di Savoia. Was the beautiful Lisa Gualanda the woman loved also by Enea Irpino, who praised a portrait painted by Leonardo in his Canzoniere?

An interesting attempt to identify the landscape was made in 1993 by Carlo Starnazzi and Cesare Maffucci, who suggested that the bridge could be identified as that of Buriano, which crossed the Arno in the vicinity of Arezzo. And this has been enough to keep the ancient bridge from being submerged by the waters of an artificial lake. But the proposed identification presents some problems, since Leonardo tended to draw inspiration from real-life observation of nature, and then to idealise it.

It is certain that Leonardo crossed the Buriano bridge; but when he drew it on map RLW 12278, datable around 1503, the representation clearly differs from that of the Mona Lisa. However, Leonardo could have crossed the bridge again around 1513-1514, when going to Rome and returning to Florence, and then represented it ideally in the landscape of the painting.

The other hypothesis, that the mountains in the background of the painting were inspired by the eroded furrows of the Valdarno, in the area around Reggello, is instead opposed to the opinion of those who recognise in it the suggestion of Alpine scenery.

It is more than probable that Leonardo drew the cartoon for a Lady on a Balcony and for the Mona Lisa during the first years of the 16 th century. Of this, as of other cartoons done in Florence, such as those of the Saint Anne and the Battle of Anghiari, no collocation is known. Raphael is thought to have drawn inspiration from this cartoon for portraits such as that of Maddalena Doni now in Florence, in the Saturn Room of the Palatine Gallery (Palazzo Pitti).

In 1739 a Gioconda was listed in the inventory of Palazzo dei Mozzi in Florence.

A fascinating painting in the key of historical romanticism, with the legendary re-evocation of Leonardo painting the Mona Lisa surrounded by musicians, is found at the Istituto Statale d’Arte [State Institute of Art] in Siena; it is a large canvas painted by Cesare Maccari at the age of 23, in 1863.

A set of engravings on the vicissitudes of the painting is exhibited in rotation at the Museo Ideale of Vinci, along with two versions of Duchamp's Mona Lisa L.H.O.O.Q.

In 1913, two years after the painting had been stolen from the Louvre by Vincenzo Peruggia, the Mona Lisa was found again in Florence, thanks to the antiquarian Geri and to Superintendent Poggi, in a room at the "Tripoli e Italia" hotel (today called "Hotel La Gioconda", located in Via Panzani 2). It was a sensational recovery; the painting was temporarily exhibited at the Uffizi and then returned to Paris, in January 1914, while its fame exploded.