The Casentino is one of the four main valleys that divide the province of Arezzo. It is the valley in which runs the first leg of the Arno River, which originates from Mount Falterona (1654 m s.l.m.). Mount Falterona, together with the Monte Falco (1658 m s.l.m.), constitutes the northern limit of the valley, on the border with Romagna. The Alpe di Serra and the Alpe di Catenaia separate, in the East, the Casentino from the Val Tiberina. To the west the massif of Pratomagno separating from the upper Valdarno. The western elevations of the complex of Monte Falterona, finally, separate the valley from the Mugello. The landscape varies from large forests of mountainous areas to the plains and hilly areas of the valley floor. The particular characteristics of the area are probably one of the causes which led Francis of Assisi to choose the Verna (now the site of a Franciscan monastery) as a place of prayer, and San Romualdo to found the Hermitage of Camaldoli. The valley is divided in 13 municipalities forming part of the Montana del Casentino: Bibbiena, Capolona, Castel Focognano, Castel San Niccolò, Chitignano, Chiusi della Verna, Montemignaio, Ortignano Raggiolo, Poppi, Pratovecchio, Stia and Subbiano Talla. The main centers of Casentino are those of Poppi, which is part of the club of “most beautiful villages in Italy” and Bibbiena, the main craft and industrial center.