Historian Donald Sassoon catalogued the growth of the painting's fame. During the mid-1800s, Théophile Gautier and the Romantic poets were able to write about Mona Lisa as a femme fatale because Lisa was an ordinary person. Mona Lisa "...was an open text into which one could read what one wanted; probably because she was not a religious image; and, probably, because the literary gazers were mainly men who subjected her to an endless stream of male fantasies." During the 20th century, the painting was stolen, an object for mass reproduction, merchandising, lampooning and speculation, and was reproduced in "300 paintings and 2,000 advertisements". The subject was described as deaf, in mourning, toothless, a "highly-paid tart", various people's lover, a reflection of the artist's neuroses, and a victim of syphilis, infection, paralysis, palsy, cholesterol or a toothache. Scholarly as well as amateur speculation assigned Lisa's name to at least four different paintings and the sitter's identity to at least ten different people.
Visitors generally spend about 15 seconds viewing the Mona Lisa. Until the 20th century, Mona Lisa was one among many and certainly not the "most famous painting" in the world as it is termed today. Among works in the Louvre, in 1852 its market value was 90,000 francs compared to works by Raphael valued at up to 600,000 francs. In 1878, the Baedeker guide called it "the most celebrated work of Leonardo in the Louvre". Between 1851 and 1880, artists who visited the Louvre copied Mona Lisa roughly half as many times as certain works by Bartolomé Esteban Murillo, Antonio da Correggio, Paolo Veronese, Titian, Jean-Baptiste Greuze and Pierre Paul Prud'hon.
From December 1962 to March 1963, the French government lent it to the United States to be displayed in New York City and Washington D.C.. In 1974, the painting was exhibited in Tokyo and Moscow.
Before the 1962–3 tour, the painting was assessed, for insurance purposes, as valued at $100 million; the insurance was not bought, instead more money was spent on security. As an expensive painting, it has only recently been surpassed, in terms of actual dollar price, by three other paintings: the Adele Bloch-Bauer I by Gustav Klimt, which was sold for $135 million, the Woman III by Willem de Kooning sold for $138 million in November 2006, and No. 5, 1948 by Jackson Pollock sold for a record $140 million on in November 2006. Although these figures are greater than the 1962 figure which the Mona Lisa was valued at, the comparison does not account for the change in prices due to inflation - $100 million in 1962 is approximately $700 million in 2009 when adjusted for inflation using the US Consumer Price Index.