The original core of the Library consists of the private collection donated by Canon Giovanni Chelli to the Commune of Grosseto in 1864. The heritage of books was severely damaged, first by bombing during World War II, then by the floods of 1944 and 1966. The Chelliana possesses a conspicuous number of ancient books, including numerous incunabula and hundreds of sixteenth-century editions, no less than 1,800 seventeenth-century ones and 2,000 eighteenth-century ones. Particularly significant, from the historical and scientific viewpoint, are the three Sienese herbariums dating from around 1765, probably compiled under the supervision of Giuseppe Baldassarri, director of the Siena Giardino dei Semplici (medicinal herb garden) from 1759 to 1780, and recently restored at the University of Pisa Botanical Garden. The dried plants are grouped in three packets, formed of folded and partially bound leaves.