On August 21, 1911, a Louvre repairman named Vincenzo Peruggia lifted Leonardo's small poplar panel off a gallery wall, hid it under his smock, and walked out through a door workmen used every day; the museum did not notice for a full twenty-four hours.

Vincenzo Peruggia had spent the better part of a year inside the Louvre, fitting glass cases over its most valuable canvases for a Paris framing firm the museum had subcontracted (he was never, technically, a Louvre employee). What he had not been given was any reason for a guard to stop him from walking out with one of those canvases himself.

How does a painting disappear from a locked museum?

On Monday, August 21, 1911, the day the Louvre closed to the public for its weekly cleaning, Peruggia let himself into a storage closet near the Salon Carré and waited out the night. Two former co-workers, brothers named Vincenzo and Michele Lancelotti, are believed to have helped him plan it, though accounts differ on how much, and only Peruggia was ever convicted; the case against the brothers never held up. Around seven the next morning, wearing the white smock issued to Louvre maintenance staff, he lifted Leonardo da Vinci's portrait of Lisa Gherardini off its four iron wall pegs and, in a stairwell, stripped away the heavy frame and the glass case he himself had helped install a year before. He wrapped the bare poplar panel, a little over two feet tall, in the smock and walked out through a service door.

Why did no one notice for a full day?

Because paintings left the walls constantly. The Louvre's photography studio regularly borrowed canvases for reproduction, and conservators pulled others for cleaning, so a bare patch of wall where a Da Vinci had hung read as routine. It took a hobbyist painter named Louis Béroud, arriving the next morning to sketch the frame he assumed the studio had simply not returned yet, to ask a guard where the picture had gone. The guard checked with the photography department, got no answer, and only then climbed to the roof on a hunch. Nothing was there. By the time museum director Théophile Homolle sealed the building and called police, the trail was already a day cold, and Paris papers ran the story before investigators had a single lead.

Who did the police arrest first?

Not Peruggia. Investigators fixed instead on Guillaume Apollinaire, the poet and critic who had once employed a small-time thief named Honoré-Joseph Géry Pieret as a secretary; Pieret had walked out of the Louvre years earlier with a pair of Iberian stone heads and sold two of them to a young painter he knew, Pablo Picasso. When police traced Pieret to the museum's long history of loose security, they arrested Apollinaire on September 7, 1911, and brought Picasso in the same week for questioning. Neither man had touched the Mona Lisa; both were released within days for lack of anything tying them to it. Detectives had also questioned Peruggia early on, since his name sat on a list of Louvre subcontractors, and let him go without a second look.

Peruggia, meanwhile, kept the painting eighteen inches from his bed.

He had built a false bottom into a wooden trunk in his one-room apartment on the Rue de l'Hôpital-Saint-Louis and left the panel there, wrapped in cloth, for more than two years while French police searched everywhere except the room across town where it actually sat.

How did the trail lead to Florence?

Money. In November 1913, writing under the alias Leonardo Vincenzo, Peruggia contacted Alfredo Geri, an antiques dealer in Florence, offering to sell a painting he described as a treasure he had rescued for Italy. He wanted 500,000 lire: something close to $100,000 at the time, and a fortune for a man who had been working as a house painter. Geri brought in Giovanni Poggi, director of the Uffizi Gallery, and the two met Peruggia at his hotel on December 11, 1913, where he pulled the panel from the same trunk he had used to smuggle it out of Paris. Poggi compared brushwork and craquelure against the Uffizi's own Leonardo holdings and pronounced it genuine within the hour. Police arrested Peruggia before he left the building.

He told the court he had acted out of patriotism, convinced Napoleon's army had looted the painting from Italy over a century earlier. That story collapsed under basic chronology: Leonardo had carried the panel to France himself, around 1516, at the invitation of King Francis I, and it had belonged to the French crown ever since. Letters Peruggia wrote before his arrest, to his father and to a politician back home, talk about money rather than national honor, and historians now read the patriotic defense as courtroom theater that happened to work on an Italian jury sympathetic to the sentiment. He was sentenced to a little over a year and released after seven months.

What was the painting worth before any of this happened?

Less than it seems now. Before 1911 the Mona Lisa was one respected Leonardo among several hanging in the Salon Carré, admired by specialists but rarely singled out by visitors who had dozens of comparable works to choose from in the same room. The theft, and the newspaper coverage that ran almost continuously for the two and a half years the painting stayed missing, did something no catalog essay had managed: it gave millions of readers who had never stood in front of the panel a reason to want to. When it went back on public display in January 1914, more than one hundred thousand people filed past it in the first two days.

Where does that leave the painting now?

Behind bulletproof glass, in a room the Louvre redesigned specifically to move crowds past it. The museum now counts close to nine million visitors a year, and its own surveys find that most of them name one painting as the reason they came, ahead of anything else in a building that holds work by Vermeer, Rembrandt, and half the canon of Western art. French officials confirmed in 2019 that a standalone Mona Lisa gallery was under study as part of a wider Louvre renovation, an acknowledgment that the current room, built for a respected portrait, was never built for a phenomenon. The trunk with the false bottom is long gone; the crowd it created is still growing.

Sources

• The Art Newspaper, "Missing Mona Lisa: the story behind the 1911 theft of Leonardo's masterpiece" (2024)
• History.com, "The Heist that Made the Mona Lisa Famous"
• TheCollector, "How Did Vincenzo Peruggia Steal the Mona Lisa?"
• History.com, "Why Pablo Picasso Was a Suspect in the 'Mona Lisa' Heist"