For the first time it was mentioned the name of Bishop Acutus in a diploma of Frederick Barbarossa in 1164, as dictated by the shape of the hill, on top of which the bunting lords, Beccaria, built a military fortress to control the mouth movements and transport of Val Versa and to protect yourself from the adversaries' attacks. In the Middle Ages the fortress was repeatedly destroyed and rebuilt during the struggles between the noble families of Milan, Pavia and Piacenza. At the beginning of the seventeenth century the last descendant of Beccaria di Pieve in Cairo, Aureliano, left the fort for testamentary use with 6000 land perches to the Congregation of Barnabiti who, in the two centuries of permanence, made Montù an educational and cultural center of great quality.