The island of Sancti Petri, with a fortress that is located off the coast of San Fernando and Chiclana in the outfall of the Sancti- Petri inlet, is where historians have located the legendary temple of Hercules. The castle is part of the fortifications built during the XVI-XVII centuries to defend the Bay of Cádiz..
The castle is built on the bedrock and occupies most of the island. The buildings that now form part of the castle can be divided into two main areas. The northern area includes the tower, which was used as a powder store, the circular main courtyard and rooms used as barracks, kitchens, and the master’s quarters.
The southern area, constructed later, in the second half of the XVIII century, were auxiliary buildings used for munitions storage and surveillance. This area was partially demolished during the storm by waves, undermining and destroying the retaining wall, with subsequent collapse of the corner overlooking San Fernando.
The castle has been object to modifications and restorations over for centuries, the last one in the XIX century. Therefore, it required guaranteed intervention which relied on technical criteria that are specific to this case. Usual criteria for renovation had to be combined with elements belonging to the historical and cultural heritage of Spain.
Moreover, due to its location in a natural reserve, access to the monument was limited, and strong environmental regulations were observed (in the pictures, from left to right, seagull eggs, old ammunition and cynomorium cocinneum).
It should be pointed out the advanced state of deterioration in which the castle was found. Most of the damage detected was due to the castle’s poor durability, because the castle is under serious environmental stress and the materials used were only of average mechanical performance and durability.