The original nucleus of the Library dates from 1473 when, thanks to the donation of Cardinal Niccolò Forteguerri, the Sapienza School was established. After the school was opened to the public in 1696, a grand-ducal decree required the Commune to finance the library. In 1730, the library’s heritage was enriched by the addition of 30 of the 110 manuscripts left to the Commune in 1458 by Sozomeno (Zomino di ser Bonifazio), which today constitute the oldest part of the collection.

Housed in Palazzo della Sapienza, the library boasts a notable heritage of books, incremented over the centuries by purchases, donations, and, since 1933, by the right to deposit of printed matter, which has contributed to making the Forteguerriana a historical library, as it still is today. At present the library possesses around 300,000 monographs, over 1000 manuscripts, 3000 sixteenth-century editions, 2790 miscellaneous folios, 126 incunabula and 300 periodicals. Among the most important repertories are, along with numerous manuscripts, sixteenth-century editions and the rich heritage of volumes on local history, the Ethiopic codexes and the papers of the Accademia Pistoiese di Scienze Lettere ed Arti.