Built in the 1st century, the tower is located on a peninsula about 2.4 km (1.5 mi) from the center of A Coruña, Galicia, in northwestern Spain.

Its base preserves a cornerstone with the inscription MARTI AVG.SACR C.SEVIVS LVPVS ARCHITECTVS ÆMINIENSIS LVSITANVS.EX.VO,[4] ascribing the tower's design to the architect Gaius Sevius Lupus, from Aeminium (present-day Coimbra, Portugal) in the former province of Lusitania, as an offering to the Roman god of war, Mars.

According to a myth that mixes Celtic and Greco-Roman elements, the hero Hercules slew the giant tyrant Geryon after three days and three nights of continuous battle.

Hercules then, in a traditional Celtic gesture, buried the head of Geryon with his weapons and ordered that a city be built on the site.

The lighthouse, standing atop a skull and crossbones representing the buried head of Hercules' slain enemy, appears in the coat of arms of the city of A Coruña.

According to another legend from the 11th-century Irish compilation Lebor Gabála Érenn—the "Book of Invasions"—King Breogán, the founding father of the Galician Celtic nation, constructed a massive tower of such a grand height that his sons could see a distant green shore from its top.

[6] Throughout the Middle Ages, multiple naval crusading itineraries to the Holy Land mentioned the obligatory stopover at the Lighthouse.

Usually, the crusader fleets would disembark there to reach the shrine of the Apostle James the Greater at Santiago de Compostela on foot.