ANN ARBOR, Mich. (WLNS) — A prized piece of the University of Michigan Library collection has been deemed a fake.

Thought to be a manuscript handwritten by Galileo Galilei himself, the document was revealed to be a forgery after an investigation by Nick Wilding, a history professor at Georgia State University.

The University of Michigan conducted its own investigation and also concluded that the manuscript was a forgery dated to the 20th century.

The fake manuscript first came to the public’s attention in 1934, after an auction sold the collection of Roderick Terry, a wealthy collector of rare manuscripts and early printed books.

According to the auction’s documents, the manuscript was authenticated by Cardinal Pietro Maffi, Archbishop of Pisa, who compared it to an autograph from Galileo he had in his possession.

The truth was discovered thanks to watermarks on the paper. The watermarks on the supposed manuscript contain monograms for the paper maker’s initials. The particular initials evident on the manuscript do not appear before 1770.

The forgery was created by Tobia Nicotra, an infamous forger responsible for other Galileo forgeries — including documents owned by Maffi.

To read more, visit the University of Michigan Library website.