The Athenian Stoa was a covered colonnade built in the 470s BC. The approximate 100 foot structure was supported by eight Ionic fluted columns. Each one was carved from a single piece of white marble. Inside were spoils seized by the Greeks during the Persian Wars (492 to 449 BC). The stoa evolved into a war memorial for subsequent Athenian battles. The back of the portico is the Polygonal Wall. These interlocking cut stones are part of the platform built in 560 BC for the Temple of Apollo (columns above the wall).