Caryatids of the Erechtheion next to the Parthenon acropolis. The 6 Caryatids have become the temple's signature feature, casually supporting the weight of the porch's roof on their heads. Their identification, or the purpose for such elaborate column treatment is lost through the centuries, but it was by no means a new feature in Greek architecture. The Syphian treasury at the sanctuary of Delphi similarly substituted female figures for columns as far back as the sixth century BCE. The Erechtheion construction was concluded in 406 BCE, and soon thereafter, in 403 BCE Athens fell to the Spartans.