**Guglielmo Libri** was an Italian mathematician who worked on mathematical physics, number theory and the theory of equations. He also published works on the history of mathematics.

- Libri's research career in mathematics began while he was still an undergraduate and he published his first paper Memoria ...
- Libri certainly took his role in the Academy very seriously but there was some resentment caused by the fact that he was not a native Frenchman, and this was somewhat increased by his own rather arrogant nature.
- His friendship with Arago was certainly helpful to Libri in obtaining prestigious posts yet soon this relationship went sour (although we do not know the reason for this) and by 1835 instead of being recognised as close friends, the pair were recognised as bitter enemies.
- Arago was a powerful figure in French mathematics at the time and counting him as an enemy meant that many in the mathematical establishment also became Libri's enemies.
- One such powerful figure was Liouville who worked for many years against Libri and the two would attack each other at every opportunity in meetings of the Academy.
- Liouville was in many ways someone who Libri should not have competed with, for he was an outstanding mathematician who could usually come up with a more elegant proof of Libri's results than he could himself.
- Libri's early work was on mathematical physics, particularly the theory of heat.
- One of the strengths of Libri's Histoire is the large number of quotes from original sources, so it was natural that Libri should be an enthusiastic collector of rare books and manuscripts.
- Libri was appointed Inspector of the Libraries of France in 1841.
- However it was soon reported that precious books and manuscripts were going missing from libraries and all these losses coincided with a visit to the library by Libri.
- There was a Revolution in France in 1848 and, shortly after this, Libri was informed that a warrant was about to be issued for his arrest on suspicion of stealing precious books.
- The Revolution had removed his friend Guizot from the government and Libri was now exposed.
- He had a fellow Italian friend in Antonio Panizzi, the Director of the Library of the British Museum, and through him Libri made friends with De Morgan.
- Now Libri was able to convince his new friends that the charges against him were made by the French because he was an Italian.
- De Morgan wrote many articles in Libri's defence.
- Certainly Libri could not return to France.
- Although Libri had arrived in England without any money he was not poor for long.
- Perhaps not surprisingly it came from the sale of many precious books and manuscripts which Libri happened to have with him when he arrived in London.
- In 1861 Libri had two major sales of his books and manuscripts in England.
- He wrote a 30 page introduction to the Catalogue of the Mathematical, Historical, Bibliographical and Miscellaneous Portion of the Celebrated Library of M Guglielmo Libri which gives a remarkably modern sounding argument for studying the history of science in general and the history of mathematics in particular.
- What are we to make of Libri's contributions here when we now know that indeed he was a thief?
- These two sales of books imported from France contain a magnificent series of manuscripts and books by Galileo, Copernicus, Kepler, Cardan, etc., many with long notes pointing out their significance, and we must not allow ourselves to be blinded to the showmanship and originality of Libri's catalogue by his unenviable reputation as a forger and a thief.
- Libri has fallen under a cloud which obscured his very real merits.
- The immediate financial results of these two sales must have been disappointing, but in them Libri gave an impetus to collecting in the scientific fields ...
- By 1868 Libri's health began to fail and, unable to return to France, he left England for his native Italy.
- After his death, Léopold Delisle began a long investigation to settle the question of whether Libri was guilty of the charges on which he was convicted in 1850.
- He showed with complete certainty that Libri was indeed a thief on a very large scale.
- In 1888 the French government requested that the precious books and manuscripts which Libri had stolen, and then sold, be made available for them to buy back.

Born 1 January 1803, Florence (now Italy). Died 28 September 1869, Fiesole, Italy.

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Origin Italy

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive