On this day in history: birth of Guglielmo Libri – scholar and book thief

Guglielmo Libri, one of the most prolific book thieves in history, was born in Florence on 1 January 1803. A nobleman, celebrated academic and later a convicted criminal, Libri is believed to have stolen more than 30,000 books, manuscripts and letters during the 19th century, many of which have never been recovered.

Born Count Guglielmo Libri Carucci dalla Sommaja, he displayed exceptional intellectual ability from an early age. At just 16, he began studying law at the University of Pisa before switching to mathematics. By the age of 20, he had secured a post as professor of mathematical physics, marking him out as one of Italy’s most promising scholars.

Libri’s early academic success was accompanied by political entanglements. While in Italy, he became associated with the Carbonari, a secret revolutionary movement opposed to absolute rule. When this involvement placed him at risk of arrest, he fled to Paris in the mid-1820s, a move that would shape both his career and his crimes.

In France, Libri’s reputation flourished. He became a French citizen in 1833 and obtained prestigious academic positions, including a professorship at the Collège de France and an appointment at the Sorbonne in probability calculus. He was also elected to the French Academy of Sciences, cementing his status within Europe’s intellectual elite.

Obsessive collector and book thief

Behind this distinguished public image, however, Libri was engaged in systematic theft. An obsessive collector of rare texts, manuscripts and letters, he had already stolen extensively from the Laurentian Library in Florence. His activities escalated dramatically after his appointment in 1841 as Chief Inspector of French Libraries, a role that gave him unrivalled access to archives across the country.

As inspector, Libri was responsible for cataloguing and assessing valuable collections held in libraries and municipal archives. This allowed him to work alone for long periods in storage vaults and reading rooms, often without supervision. He could legally remove documents for research purposes, with little expectation that they would be returned.

When direct removal was forbidden, Libri relied on subterfuge. He habitually wore an oversized cape, claiming poor health as justification even during summer months. Beneath it, he concealed books and manuscripts as he left the libraries he was meant to protect.

Suspicion gradually grew, but it was not until 1848 that French authorities issued a warrant for his arrest. By then, Libri had been warned and had already escaped to London, transporting around 18 trunks filled with stolen material.

What did Guglielmo Libri steal?

Among the items taken were 72 letters by philosopher and mathematician René Descartes, as well as the Tours Pentateuch, a rare illuminated Latin manuscript dating from the late sixth or early seventh century. The Pentateuch was stolen from the Library of Tours and later sold to the 4th Earl of Ashburnham, after which it became known as the Ashburnham Pentateuch.

With no extradition treaty between France and Britain at the time, Libri avoided arrest. He was tried in absentia in 1850 and sentenced to ten years in prison, a penalty he never served. Instead, he lived comfortably in England, financing his lifestyle by selling rare books to private collectors and at auction. Two sales in 1861 reportedly earned him more than one million francs.

Libri’s scholarly output was also tainted by theft. His four-volume History of the Mathematical Sciences in Italy, published between 1838 and 1841, drew on around 1,800 manuscripts and books by figures such as Galileo, Descartes and Leibniz. Many of these works, he later admitted, had been taken from public libraries, including the Laurentian Library.

He remained in England until 1868, when declining health prompted his return to Italy. Libri died the following year in Fiesole, near Florence, aged 66.

While many of the items he stole remain missing, occasional discoveries continue to surface. In 2010, one of the stolen Descartes letters was identified at Haverford College in Pennsylvania.