Sacred Caves and the Bronze Tower
I have mentioned sacred caves on this blog before, when I discussed my book Knossos. Much of the information on sacred caves in Greece centers around the caves of Crete, but caves and cave sanctuaries were important in mainland Greece, too,
One of the earliest human habitations in Greece was the Franchthi Cave in Argolis, a Paleolithic site in use around 38,000 B.C. There was a cave, too, on the hill of Argos, just below the hilltop citadel of Larissa. It was used as a place of worship, and probably served as the very first temple to Hera; the Heraion of Argos, the temple of later, historical times, stands above ground.
Sacred caves were associated with women, fertility, and chthonic rites. In the Danae legend, when King Acrisius learns that he will die at the hands of his daughter's son, he shuts Danae away from all contact with men. Some versions state that he built a bronze tower, others that was a subterranean chamber. But bronze was high technology in the fourteenth century B.C. when these events would have taken place; kingdoms rose and fell according to a ruler's ability to obtain bronze and shape it into weapons for war. Acrisius would not have wasted precious copper and tin on constructing a vault or tower for his daughter.
In all probability, a king of Mycenaean Greece would have confined a daughter who was to remain a virgin in an underground space: a cave. It's both a descent into living death (Danae is not to live on through the children she is never supposed to have) and into the mysterious, forbidding realm of the female mysteries (Danae, who may or may not have started menstruating at this point, is to live her life surrounded entirely by women).
For Danae, I could have used the Argos cave, but I wanted Danae's exile to be more productive than just her wiling away the days in isolation. I needed her to learn the practical skills she would need later on, during her exile on Seriphos. And I needed her to gain a sense of self that she could not acquire right under her father's nose. So I hit upon a sacred cave somewhere in the Parnon Mountains, a wilderness inhabited by servants of the goddess Artemis.
You should not go looking for the Sanctuary of Potnia Theron on the Argolid-Spartan-Arcadian border. It is not a real site, but an imagining of what such a place might have been like. There are real cave sanctuaries with "goddess-pillars" of the type described in Danae. Also, Arcadia was seen as a physical and cultural backwater, the last stronghold of the pre-Mycenaean Greek "Pelasgian" inhabitants. The Women of the Mountain represent pre-Greek culture in the process of being assimilated into the Mycenaean "Koine."