The origins of the library go back to the early 5th-century when the Scriptorium, a place dedicated to writing, was founded and the first manuscripts were rewritten by the churchmen. Throughout time the church has been rebuilt each time larger than the previous version as there was a need for more space. The scriptorium was also enlarged because the number of books stored constantly increased. In the  12th-century the Scriptorium was no longer used for rewriting books instead it started functioning as a library.

The library is also related to notable people such as Dante Alighieri, the father of the Italian language, and Francesco Petrarca, a scholar and a poet. In 1320 in the church that belongs to the same complex Dante held his dissertation and Petrarca was invited to the library to consult the books in 1345.

Luckily, even though Biblioteca Capitolare was severely destroyed in 1945 by bombs, the librarian Turrini had been removing books from the library and hiding them in the small town in the mountains. So, after the restoration of the great hall,  books were brought back with some of them still showing signs of damage from the bomb explosion.

In  2017 the library was opened to the public.