Castello di San Terenzo: rilievo aerofotogrammetrico delle mura, analisi del degrado e progetto di restauro conservativo

The Castle of San Terenzo is located in the hamlet of Lerici, in the Gulf of Poets, in the province of La Spezia. The first indirect evidence of a castle in the area dates back to 1360, with the mention of a certain Rossi as the castellan. The original fortification consisted of a watchtower built by the Republic of Genoa, with a quadrangular base measuring about 7x7 meters, walls one meter thick, and a height of ten meters. Subsequently, the castle was expanded with a first surrounding wall in the 15th century, capable of hosting eight crossbowmen and equipped with loopholes and three watchtowers. With technological advancements, a second surrounding wall was added in the 16th century, characterized by an irregular pentagon shape with three angles facing the village and corresponding turrets with a sloped base. This latter expansion phase was likely carried out by the villagers to protect themselves from Saracen pirate invasions, hence its local name “Bastia.” During World War II, the castle was occupied by German troops, who built a bunker and an anti-landing wall. After the war, it was used as a photoelectric station, and a “parasitic” structure was built, which is still used today for visitor reception. In 2013, the castle underwent internal renovations, including new paving on the terraces and safety parapets. Today, the Castle of San Terenzo is part of the Ligurian Museum Network and hosts temporary exhibitions. During the 2017/2018 academic year, I carried out, on behalf of the University of Pisa, a restoration project of the walls, given their state of neglect and decay. The survey was conducted using modern aerial photogrammetry with a drone, and the data was processed using Structure from Motion technology. The restoration project involves the restoration of plaster to protect the structure from the harsh marine environment, the removal of invasive vegetation, and the consolidation of the walls showing signs of collapse.