The ‘Earlier Mona Lisa’: Proposed timeline and Succession of Events.

1452 Birth of Leonardo da Vinci.

1479 Birth of Lisa Camilla Gherardini (Mona Lisa).

1500 Leonardo returns to Florence from Milan, via Mantua and Venice.

1501 Letter of Fra' Pietro da Novellara to Isabella d'Este: Document suggests that Leonardo might have begun work on two Mona Lisas.

1503 The Heidelberg Document: Agostino Vespucci witnesses Leonardo painting the portrait of Mona Lisa in a manner that will leave it "unfinished".

1504 Raphael Sketch: 'A Young Lady on a Balcony' with side columns based on Leonardo's 'Mona Lisa'. Raphael's subsequent painting: 'Lady with a Unicorn', follows a similar composition.

1505 Leonardo leaves his 'Earlier Mona Lisa’ unfinished.

1506 Leonardo leaves Florence: Del Giocondo most likely receives the 'Earlier Mona Lisa’.

1508 Glazing technique: Leonardo develops a glazing technique which is conspicuous in his paintings from this time including the Louvre 'Mona Lisa'.

1513 Leonardo arrives in Rome: He works under the patronage of Giuliano de' Medici.

1516 Departure for France: Leonardo leaves Rome for Cloux.

1517 The visit in Cloux: Cardinal Luigi of Aragon and his secretary Antonio De Beatis visit Leonardo, and he shows them the 'Mona Lisa', which is described as a finished painting. It is the painting in the Louvre today.

1550 Giorgio Vasari's compendium 'The Lives of the Most Excellent Italian Architects, Painters and Sculptors': He states that Leonardo painted a portrait of Lisa Gherardini for her husband Francesco del Giocondo and after working on it for four years, left it unfinished.

1584 Gian Paolo Lomazzo treatise on art history: He states that Leonardo painted a 'Gioconda', and a 'Mona Lisa'.

1730-50 The Grand Tour: The 'Earlier Mona Lisa' is acquired by an English nobleman and brought to Somerset, England.

1913 The Great Discovery: Hugh Blaker locates and rediscovers the 'Earlier Mona Lisa'.

1914 First World War: The 'Earlier Mona Lisa' is sent to Boston, USA for safekeeping.

1915 Introducing the Case: Publication of John Eyre's monograph on the 'Earlier Mona Lisa'.

1922 Connoisseurs see the painting: The ‘Earlier Mona Lisa’ is brought to experts in Italy.

1924 A second publication: John Eyre's second book: 'The Two Mona Lisas'.

1936 Exhibition: The 'Earlier Mona Lisa' is exhibited at The Leicester Galleries, London.

1951 Public reference: Encyclopedia Americana lists the 'Earlier Mona Lisa'.

1962 Changing hands: Dr. Henry Pulitzer acquires the 'Earlier Mona Lisa'.

1975 Locked away: The 'Earlier Mona Lisa' is brought to Switzerland and locked in a bank vault.

1979 Elisabeth Meyer inherits the painting following Pulitzer's death, but the painting remains in its vault.

2008 International consortium acquires the ‘Earlier Mona Lisa’ after Elisabeth Meyer dies.

2010 The Mona Lisa Foundation is established and mandated to complete all research on the painting.

2011 The ‘vox populi’ test: The painting is exhibited in Japan without any of the Foundation’s findings, to gauge public reaction.

2012 The Mona Lisa Foundation publishes the findings of 35 years research and tests in its book 'Mona Lisa - Leonardo's Earlier Version'.