Hoping to establish trade contacts, in the year 61 A.D. Julius Cesar led an expedition that arrived by sea to Brigantium. This arrival led to the founding of a strategic colony at the limits of the empire, then later to the construction of an important port for the rear guard during the Cantabrian Wars.

Trade relations were expanding during the Pax Romana initiated by Augustus, which led to the construction of a road network and an increase in maritime traffic to promote the process of Romanization. Within this context the northwestern Iberian Peninsula became essential territory, and the port of Brigantium become one of the main points of arrival for Road XX as well as the place where the Roman fleets took refuge on their way to the conquest of Britain.

This military interest is what allowed the Roman Empire to justify construction of the lighthouse. Up until then, navigation from Gibraltar to Fisterra had taken place parallel to the coast just a 17 few miles from shore, following the route of Road XX (also known as per loca marítima). However, at Brigantium the ships now had to turn their bows towards the English Channel and the territories to the north, entering into an exposed stretch of ocean that could be extremely rough and dangerous.

Construction of the lighthouse fulfilled the mission of orienting and guiding the sailors in the immensity of the ocean.