Established in 1868, the Library possesses a collection of manuscripts that belonged to Giuseppe Ghizzi, author and first librarian, donated in part by himself and, subsequently, by his widow Eleonora Gnagnoni. Especially interesting among the documents is the Hortus Siccus Pisanus, a herbarium dating from the 18th century. By an unknown author, the herbarium presents 300 samples of herbs, arranged in alphabetical order. The Library also contains magazines from the 18th and 19th centuries and the series of Leopoldian decrees, charts and land office maps relevant to the territory of Castiglion Fiorentino. The Library, first located in Palazzo degli Scolopi, was subsequently housed at various places, until being moved to Palazzo Pretorio, its present location, in 1999.