Matilda’s castles, northern Apennines: geological and geomorphological constrains

The positioning and construction of castles in ancient times responded not only to strategic opportunity, but also to the issue of geomorphological risk. We investigated castles and strongholds built in the era of the Great Countess Matilda of Canossa in part of the northern Apennines (Italy), in order to study the relationship between their positioning and the distribution of geomorphological and geological hazards. We observe how the location of castles follows clear patterns of avoidance of potential hazards: Castles are kept far from the main fault systems and stream networks, and are mainly at a safe distance from landslide- and badlands-susceptible terrains. The knowledge of Medieval communities on landscape hazards was sufficiently advanced to minimise risks, while maintaining the strategic value of fortifications.