Comunicazione ottica e sonora tra Medioevo e Rinascimento: sistemi di segnalazione per la difesa del territorio italiano

The defence techniques since the Middle Ages based on optical and sound signals were crucial for security and communication between outposts, adapting to the specific needs of both inland and coastal contexts. This paper examines how the long-distance message transmission system, using nighttime torches and daytime smoke signals, often accompanied by auditory signals such as gunshots or the ringing of bells, enabled a well-structured defense against enemy incursions. The analysis focuses on two main categories of defensive structures: coastal towers and inland towers, which were the key architectural elements for effective optical signaling systems. Specific cases are discussed, such as the continuous system of towers along the coast of the Kingdom of Naples, designed to counter raids by pirates and barbarian invaders, and the use of fani (beacons), small towers distributed along the coast, designed to defend against raids by pirates and barbarian invaders. The article also explores the role of towers in the hinterland, such as the Bologna municipal fortifications, which combined functions of observation and defence against external and internal threats. The role of torrari (watchtower keepers), responsible for the surveillance and transmission of signals in case of sightings of enemies or other emergencies, is also analysed, highlighting their importance in protecting inhabited areas and surrounding territories. In summary, the study shows how defence techniques in Italy were meticulously organized and adapted to specific territorial needs, using optical and sound signals to ensure effective protection against enemy incursions and to strengthen the security of the territories.