The library was established by bequest of Luciano Benincasa in 1669, whose will states that his private collection is to be made accessible to public use.
In 1911 the historical archive was merged with that of the municipality, and in 1925 moved again to the former convent of San Francesco delle Scale.
During World War II, the convent of San Francesco was destroyed as a result of British bombing (1943/1944), and the historical collections – with their nineteenth-century inventories – suffered serious damage.
After the war the city bought the Casa Mengoni-Ferretti, and in 1950 the library was reopened in the new premises.
The collection also includes a Fondo Musicale with 241 musical manuscripts of more than 50 composers (among them Luigi Boccherini, Arcangelo Corelli, Joseph Haydn).