Ancient accounts suggest that Roman leaders Julius Caesar, Hannibal and Scipio Africanus worshipped at the Temple of Hercules Gaditanus, a religious sanctuary in what is now southern Spain. But the pilgrimage site’s exact location has long remained a mystery.
Now, researchers say they’ve discovered the ruins of that fabled temple—one of the “holy grails of archaeology,” according to Jesús A. Cañas of El País—in a shallow channel in the Bay of Cádiz. Using digital terrain modeling, the team detected a nearly 1,000-foot-long, 500-foot-wide structure that is only visible at low tide.
“We researchers are very reluctant to turn archaeology into a spectacle, but in this case, we are faced with some spectacular findings,” Francisco José García, an archaeologist at the University of Seville, tells El País. “They are of great significance.”
García and Ricardo Belizón Aragón, also of the University of Seville, presented their findings last month at the Andalusian Institute of Historical Heritage’s Underwater Archaeology Center (CAS). Per a statement, the scholars’ light detection and ranging (LiDAR) survey revealed a submerged structure that matches ancient descriptions of the temple, which derives its name from the mythical hero Hercules.
“[Our] objective was to trace the paleolandscape back 3,000 years in an area that has been very exposed to sea oscillations,” Aragon tells the London Times’ Sabrina Penty. The team’s efforts uncovered a “totally anthropized coast, with a large building,” he adds.
Built by the Phoenicians around the eighth or ninth century B.C.E., the sanctuary reportedly featured enormous bronze carvings of the 12 labors of Hercules. Also known as the Temple of Melqart, it boasted grand columns and an eternal flame maintained by a priest. The house of worship was an important pilgrimage site for ancient Greeks and Romans.
In Greek mythology, Hercules was the son of Zeus, the ruler of all the gods on Mount Olympus. He was a demigod of superhuman strength who protected his people from a succession of monsters and villains.
According to El País, the Temple of Hercules Gaditanus appears in classical literature as the place where Julius Caesar wept when he saw a depiction of Alexander the Great and Hannibal offered tribute for victory in his military campaigns on the Italian Peninsula.
These same sources describe “a changing environment, in contact with the sea, subject to the changing tides, in a temple where there must have been port structures and a seafaring environment,” Milagros Alzaga, head of CAS, tells El País.
The large, rectangular structure identified by the researchers lies in a marshy area near the castle of Sancti Petri, between the towns of Chiclana de Frontera and San Fernando. Its foundations are roughly the same size as the island it once stood on. In addition to the proposed temple, the LiDAR survey detected an inner harbor or dock just south of the site, which was a flood zone until about two centuries ago, when water levels began to rise.
Some experts are skeptical of the new findings, arguing instead that the temple’s true location lies elsewhere. Antonio Monterroso-Checa, an archaeologist whose 2020 study concluded that the shrine is most likely located on the Hill of the Martyrs in nearby San Fernando, tells the Times that the scholars made “a triangulation error.”
The Seville team plans to conduct more fieldwork to confirm its findings. Conditions at the site make further study challenging, as the ruins are underwater most of the time.
“These are areas that are difficult to work in and have poor visibility,” Alzaga tells El País.