An invaluable historical archive has been destroyed in clashes between protesters and the Egyptian army, reports the Associated Press. The Institute of Egypt, a research center established by Napoleon Bonaparte during France’s invasion of Egypt in the 18th century, went up in flames over the weekend. The building was on the front line of a street battle in downtown Cairo that left 14 dead and hundreds wounded.

The institute housed 192,000 books, journals, and priceless historical documents like the 24-volume Description de l’Egypte, a first-of-its-kind catalog of the country’s ancient monuments,  landmarks, and customs, on which 150 French scholars and scientists who accompanied the Napoleonic expedition labored for 20 years.

Volunteers are sifting through mounds of charred books that have been transported to Egypt’s main library. Government officials have bemoaned the loss of the unique historical archive and said they will investigate how the fire started.