Gavi was built by incorporating a pre-existing castle built, according to legend, at the time of the Saracen occupations and anointed by Princess Gavia who had established her residence in that location. The first document that testifies to the existence of the castle is a notarial act dating back to the year 973.
The castle remained the property of the Genoese, albeit with ups and downs, at least until 1418 when it passed first to the Milanese Lordship of the Visconti, then to the Fregoso family and finally to the Alexandrian Guasco, lords of Francavilla.
Over the centuries the transformation from castle to fort has been slow but constant: the first radical interventions on the original structure were made in 1540 by the military engineer in the service of the Republic Giovanni Maria Olgiati.Disarmed in 1859, the fort was transformed into a civil penitentiary. During the First World War it was used as a prison camp for the Austro-Hungarians, while during the Second World War it was used as a prison camp for Anglo-American officers. The fortress can be visited in the various main rooms.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.