Galileo Galilei was peering through a new telescope in 1610 when he noticed something strange: several bright objects flickering around the planet Jupiter that seemed to change positions nightly. His discovery, of moons orbiting Jupiter, was a major crack in the notion, widely held since antiquity, that everything in the universe revolved around the Earth.

The finding, which was condemned by the Catholic Church, helped prove the theory of a sun-centered solar system.

For decades, the University of Michigan Library has prized a manuscript related to the discovery, describing it as “one of the great treasures” in its collection. At the top is the draft of a letter signed by Galileo describing the new telescope, and on the bottom are sketches plotting the positions of the moons around Jupiter — “the first observational data that showed objects orbiting a body other than the Earth,” the library described it.

At least it would be if it were authentic. After Nick Wilding, a historian at Georgia State University, uncovered evidence suggesting the manuscript was a fake, the library investigated and determined that he was right: The university said Wednesday it had concluded that its treasured manuscript “is in fact a 20th-century forgery.”

“It was pretty gut-wrenching when we first learned our Galileo was not actually a Galileo,” Donna L. Hayward, the interim dean of the university’s libraries, said in an interview. But since the purpose of any library is to expand knowledge, she said, the university had decided to be forthright about its findings and publicly announce the forgery. “To sweep it under the rug is counter to what we stand for.”

Wilding, who is writing a biography of Galileo, has uncovered forged Galileo works before: He previously found evidence that a copy of Galileo’s 1610 treatise “Sidereus Nuncius” (“Starry Messenger”), with several watercolors, was a fake. He became suspicious of the Michigan manuscript in May while examining an online image of it. Some of the letter forms and word choices seemed strange to him, and even though the top and bottom were supposedly written months apart, the ink seemed remarkably similar.


“It just kind of jumps out as weird,” Wilding said. “This is supposedly two different documents that happen to be on one sheet of paper. Why is it all exactly the same color brown?”

Wilding, who teaches a summer course on forgery at Rare Book School at the University of Virginia, began to research the Michigan document, and found there was no record of it in Italian archives. It first appeared at auction in 1934, when it was purchased by a Detroit businessman, and it was bequeathed to the university in 1938 after his death. Wilding emailed the library in May to ask for more provenance information and to request an image of the document’s watermark — an insignia visible when held to the light that can indicate where and when the paper was made.

Pablo Alvarez, the curator at the library’s Special Collections Research Center, recalled the sinking feeling he got when he saw Wilding’s name on the email, knowing his reputation for unmasking forgeries. He retrieved the document from storage and photographed its watermark, a circle with a three-leafed clover and the monogram, “AS/BMO.”

The provenance information raised red flags: The auction catalog said it had been authenticated by Cardinal Pietro Maffi, an archbishop of Pisa, Italy, who died in 1931, who had compared it to two Galileo autograph documents in his collection. Those documents, Wilding discovered, had been given to him by Tobia Nicotra — a notorious 20th-century counterfeiter in Milan.

“As soon as I heard the word ‘Nicotra,’ I got the little ‘Spidey sense,’” Wilding said.

Alvarez drove the document over to Michigan’s conservation laboratory, where Amy Crist, the library’s book and paper conservator, found that the ink and paper were consistent with the period — giving Alvarez a glimmer of hope that it was authentic.


Wilding’s search for the monogram turned up another Galileo document at the Morgan Library & Museum in New York, which had a slightly different watermark with the same monogram. That document, a 1607 letter to an unknown recipient, almost exactly matched a letter Wilding discovered in Italian archives — raising Wilding’s suspicions. He reached out to them with his concerns as well.

By early June, Wilding had determined that “BMO” was used as an abbreviation for the Italian city of Bergamo, and found a reference work called “The Ancient Paper-Mills of the Former Austro-Hungarian Empire and Their Watermarks” with information on paper from the city. Both Michigan and the Morgan, it turned out, had copies. Wilding contacted Alvarez and Philip S. Palmer, the head curator of the Morgan Library’s department of literary and historical manuscripts, telling them the answer was there.

Rushing to examine the book, Alvarez discovered the watermark on the Morgan letter, which matched documents in the reference book that dated to 1790. Alvarez couldn’t find the exact type of watermark found on Michigan’s manuscript, but no other document with a “AS/BMO” watermark appeared before around 1770 — making it highly unlikely that Galileo could have used the paper more than 150 years earlier.

Alvarez was crestfallen. “That’s it,” he thought. “Checkmate.”

Although Michigan’s document had been authenticated by Galileo scholars in the past, he felt responsible for not recognizing it earlier. “The foundation of science is observation,” he said, lamenting that he had not “really done what Galileo was actually doing.”

Palmer, at the Morgan Library, said in an interview that he accepted Wilding’s findings that the 1607 letter was not a genuine Galileo, and that the library would update its catalog to note that it was “formerly attributed to Galileo.”

In his research into Nicotra, Wilding learned the Italian had reportedly started selling fake letters and musical manuscripts to support seven mistresses. An investigation into a dubious Mozart manuscript led the police to raid his Milan apartment in 1934, finding a virtual “forgery factory,” Wilding said, with endpapers ripped from old books and fakes from Lorenzo de’ Medici, Christopher Columbus and other historical figures.

Scholars warn that there are likely other false documents in collections waiting to be discovered.

“There are definitely more forgeries out there,” said Hannah Marcus, an associate professor in Harvard’s department of the history of science who is writing a book with Paula Findlen of Stanford University about Galileo’s correspondence. She commends Wilding on the work he’s done in exposing fakes. “Not everything has to be read with an air of suspicion,” she said, “but everything needs to be read with a careful eye.”