16th century...
If the Tower of Hércules served as a fort and quarry during the Middle Ages, beginning in the 16th century the process of its conservation and the recovery of its function as a lighthouse was slowly begun.
In the 16th century, because of its advanced position in the ocean, the Tower – known as Castillo Viejo or the lighthouse Tower –, remains a watchtower against possible threats and attacks from the sea. This checkpoint was under the responsibility of the City Council, who paid the people who carried out that responsibility day and night. From the excavations done and the documentation conserved, it appears that the now was now surrounding by a small moat and a defensive parapet supplemented with barbed barriers. Surveillance in the Tower was done by sailors or retired marines; found from these people were the remains of white ceramic pipes and bone plates with round holes for buttons, evidence of their daily activities at the foot of the Tower.
17th century...
If the Tower of Hércules served as a fort and quarry during the Middle Ages, it would be the late 17th century when the Tower of Hércules would recovers its role as a lighthouse.
It would be the late 17th century when the Tower of Hércules would recovers its role as a lighthouse. In 1684, the Governor and Captain General of the Kingdom of Galicia – the Duke of Uceda – ordered the construction of a wooden staircase to allow access to the top of the Tower. To do so, the Roman barrel vaults separating the three floors of the Tower were pierced. On the northern side of the top part, a small balcony was built in order to facilitate surveillance.
Taking advantage of the new access, the Consuls of England, Holland and Flanders proposed building at the top of the Tower – at their expense –two small stone turrets, each with a light equipped with three oil lamps that would be lit every night to help navigation. The work was authorised by the Duke of Uceda and – carried out by A Coruña native architect Amaro Antúnez – the Tower regained its original function as a lighthouse. To pay for its construction and maintenance of the two lighthouse lamps, a new tax was created which was to be paid by all ships docking in to the Galician ports.
18th century...
It was soon showed that the lighthouse lamps of the Tower were insufficient. In the 18th century, there were repeated attempts to improve and repair the Tower, but they were never completed. The conditions progressively worsened: firstly, one of the lamps stopped working and then, in 1769, lightning destroyed the remaining one. As a temporary measure to replace the damaged light, three portable lights were installed; these were impossible to light when the weather was bad. The steady deterioration of the Tower and the possibility of its collapse forced major repairs, but the lack of resources prevented them from being carried out.