“We certainly know that Zeus and a female version of Zeus were worshiped in prehistoric times,” Dr. Davis continued in an e-mail message. “The trick will be in defining the precise nature of the site itself before historical times.”

Ken Dowden, director of the Institute of Archaeology and Antiquity at the University of Birmingham, in England, who was not involved in the research, said that it was not surprising to find the migrating Greeks adapting a sanctuary dedicated to gods of an earlier religion for the worship of their own gods. “Even Christians would on occasion reuse a pagan sanctuary in order to transfer allegiance from the preceding religion to Christianity,” he noted.

“You have some god being worshiped on a mountaintop, and the arriving Greeks have translated the god as ‘Zeus,’ their god of the sky, lightning, weather and so on,” Dr. Dowden said. “It’s going to be pretty close to what they found there, and given the site, it makes very good sense.”

The affinities of Roman gods and goddesses to earlier Greek ones are well known. Jupiter, for example, is a virtual stand-in for Zeus. In antiquity it was perhaps no heresy to have different names for the same deity. The place of Mount Lykaion in practices venerating Zeus is documented in literature and previous archaeological research.

Image Potsherds from the pre-Greek civilization that worshiped an unknown deity there. Credit... University of Pennsylvania Museum of Archaeology and Anthropology

The Greek traveler Pausanias, writing in the second century A.D., described the sanctuary of Zeus on the mountain, 4,500 feet above the rural countryside.

“On the highest point of the mountain is a mound of earth, forming an altar of Zeus Lykaios, and from it most of the Peloponnesus can be seen,” Pausanias wrote. “Before the altar on the east stand two pillars, on which there were once gilded eagles. On this altar they sacrifice in secret to Lykaion Zeus. I was reluctant to pry into the details of the sacrifice; let them be as they are and were from the beginning.”