A large, nearly square building situated in part over an earlier building complex (early 6th cent. B.C.) that may have served as a meeting place of an early council. In the Bouleuterion (Council House) met every day the 500-member Cleisthenic Boule (Council), which had replaced an an older, 400 member body. This group prepared the legislative bills that were normally voted on in the Assembly of the People (Ekklesia of the Demos). The building was the site of the worship of the Mother of the Gods and housed not only her cult statue (attributed to Agorakritos or less probably to Pheidias) but also the public archives of the city. Its foundations are preserved under the Metroon, a building of the 2nd cent. B.C.

METROON (150 B.C.) A prostyle building with four rooms, inside which were kept public documentsː decrees, law codes, financial records, catalogues of ephebes and of votives, along with legal documents. Also, the second room from the south housed the temple of the Mother (Meter) of the Gods, from which the name of the building, Metroon, derives. Her altar probably stood immediately east of the Metroon, on "West Street". From its destruction in A.D. 267 by the Heruli until Byzantine times, parts of the building probably served as a tavern, a synagogue, and an oil press."