This unique 18th-century coastal castle called del Cardenal was built in honor of the Infante of Spain D. Luis de Borbón y Farnesio, brother of King Carlos III and sixth son of King Felipe V of Spain and Isabel de Farnesio, Duchess of Parma.
He was appointed Cardinal Archbishop of Toledo in 1735, primate of Spain, Archbishop of Seville in 1741, and when he left the ecclesiastical state, he was named Count of Chinchón, and was an important patron who supported painters such as Francisco Goya and Luis Paret.

This fortress, along with the Prince's castle in CEE, was built between 1755-1757 for the defense of the port, in the Ría de Corcubión.

The building is a fortified peninsula in the shape of a star, built in stone, with materials from local quarries, which were a burden for the neighbors who had to bring carts and oxen to transport the stone from the quarries to the castle.
With these construction characteristics, the intention was for the piece to blend in with the surroundings and surprise attackers, preserving the security of expeditions heading to northern Europe or the Mediterranean, as well as avoiding looting of cities inland.
It has 17 cannon ports and occupies an area of approximately 2,800 m2. Inside the enclosure, surrounding the parade ground, there is a U-shaped building, which now serves as a residential area but originally was a barracks for troops, storage, powder magazine, and other castle facilities. It had a capacity for 96 men.

The interior of the building is a single storey, with 3 stone bodies, a kitchen, an officers' quarters, and storage for supplies and gunpowder, all with barrel vault ceilings, whitewashed walls to protect against diseases (which can still be seen in what is now the cellar), and a roof made of local tiles.
It also had orchards inside and a freshwater well for subsistence in case of a siege.
The fortress is in excellent condition and faithfully respects its original structure.