The bouleuterion housed the boule or council of a Greek polis in the form of a roofed meeting space. Most, if not all, cities had one; the remains of more than fifty buildings are extant. Although there were also bouleuteria in large sanctuaries and federal capitals, the major examples are urban. Bouleuteria were almost always located near a city’s agora. Over time their architects designed increasingly unobstructed interior spaces.Construction of dedicated bouleuteria began in the late archaic period; earlier councils may have met in porticoes or other buildings. Councils were generally composed of 100–500 bouletai and required a capacious meeting place; the bouleuterion became one of a city’s largest secular buildings. In the 5th and 4th centuries bce, the usual form was a hypostyle hall with symmetrically spaced interior columns, level floors, and seating on benches, as at Argos and Athens. Sloping stone seating was introduced early in the Hellenistic era and became standard; both rectilinear and curvilinear versions are known, the latter much more common. Secondary meeting spaces for committees of prytaneis or probouloi were sometimes adjacent.