Athenian Agora - The New Bouleterion (Senate House)
The southwest corner of the Agora housed the buildings that were most important for the administration of the ancient city. Next to the round Tholos (the headquarters of the 50 'presidents') was the Bouleterion or Senate House.
This was the building where the 500 members of the Athenian Boule or 'Senate' held daily meetings (except on days of religious festivals) and discussed new legislation and other matters concerning the administration of their city-state. The first or 'Old Bouleterion' was built around 500 BC, after Kleisthenes, as part of his political reforms, had instituted the Senate of Five Hundred, composed of 50 delegates for each of the ten new tribes of Athens. This 'Old Bouleterion' was almost square and measured ca. 23 x 23 m. Little of it remains to be seen, with the exception of some nice polygonal masonry beneath the east wall of the later Metroon.
A New Bouleterion was built towards the end of the 5th century BC, probably in the years from ca. 415 to 410 BC. It is not clear why a new building was needed, especially since the Old Bouleterion was not destroyed or demolished but put to use as an archive.
The New Bouleterion was somewhat smaller than the old one, measuring 16 x 22 m, and was located directly to the west of its predecessor. As in the Old Bouleterion, there is no sign of the actual seats, which must have been of wood, and the internal arrangement of the building remains a mystery.