The fifteenth century Inverno e Monteleone castle complex was founded by the Knights Hospitaller at the time of the Crusades. It was built on a rectangular plan with a central courtyard, towers at the corners, moat and ravelin. Two of the towers have square bases and the other two are cylindrical, an unusual choice in the Pavia area. Much altered over the centuries it maintained its importance at length and, up to recent times, its bell marked the rhythms of the day from the tallest tower.