The West Chamber of a double cistern lying between the northeast corner of the Theseion and the Annex to the Stoa of Zeus Eleftherios. ... Both chambers went out of use as water containers simultaneously ... 225-165 B.C.
Roman Group L.
Layer I (cont. 59-64) Pre-Herulian second half of 3rd c. (bottom, 15.95-13.90).
Layer II (cont. 42-58) 4th c.-first quarter of 4th c. (11.90-13.90).
Layer III (cont. 17-41) -4th c. (10.00 ... Second half 3rd c.-early 5th c. A.D.