University of Michigan’s prized ‘Galileo’ doc turns out to be a forgery

Annotations recording Galileo's discovery of the four moons of Jupiter, from the single leaf manuscript in our collection. (University of Michigan Library)

A document considered to be the crown jewel of the University of Michigan library collection has been exposed as a fake.

A Georgia State University professor of history named Nick Wilding looked into the authenticity of a document alleged to be written by Galileo himself in 1609 and 1610. He found that the document was likely a fake and alerted the university.

The manuscript allegedly showed Galileo’s official presentation of a recently built telescope to the Doge of Venice on August 24, 1609. The bottom half contains draft notes recording Galileo’s telescopic observations of the moons of Jupiter from January 7–15, 1610.

The university said earlier this month that following an internal investigation of the findings, the University of Michigan Library has concluded that its “Galileo manuscript” is a 20th-century fake, most likely executed by the well-known forger Tobia Nicotra.

“The historian, Nick Wilding, author of forthcoming biography of Galileo, raised a number of questions about the document, the most decisive of which was the dating of the paper. Specifically, the monograms in the paper’s watermark date the paper to no earlier than the eighteenth century. He also discovered a similar Nicotra Galileo forgery — a letter to “an unnamed person of rank” that claims a 1607 origin — held by the Morgan Library in New York City.”

The university said the findings “will require a reconsideration of its place in the collection, beginning with an update to its metadata.”

The document gained public attention back in 1934, according to U-M, when the auction firm American Art Anderson Galleries was selling the library of the late Roderick Terry, a wealthy collector of manuscripts and early printed books. According to the auction catalog, it was authenticated by Cardinal Pietro Maffi (1858-1931), Archbishop of Pisa, who compared this leaf with a Galileo autograph letter in his collection.

It was acquired by Tracy McGregor, a Detroit businessman and avid collector of books and manuscripts. After his death, the Trustees of the McGregor Fund bequeathed the manuscript to the University of Michigan in 1938, in special recognition of the services to astronomy by Heber D. Curtis, professor of astronomy.

There is no trace of the document prior to 1930.

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Ken Haddad is the digital content and audience manager for WDIV / He also authors the Morning Report Newsletter and various other newsletters. He's been with WDIV since 2013. He enjoys suffering through Lions games on Sundays in the fall.