Erechtheum (ĭrĕkˈthēəm) [key] [for Erechtheus], Gr. Erechtheion, temple in Pentelic marble, on the Acropolis at Athens. One of the masterpieces of Greek architecture, it was constructed between c.421 B.C. and 405 B.C. to replace an earlier temple to Athena destroyed by the Persians. Its design is sometimes ascribed to the architect Mnesicles. The Erechtheum contained sanctuaries to Athena Polias, Poseidon, and Erechtheus. The temple displays the finest extant examples of the Greek Ionic order. The requirements of the several shrines and the location upon a sloping site produced an unusual plan. From the body of the building porticoes project on east, north, and south sides. The eastern portico, hexastyle Ionic, gave access to the shrine of Athena, which was separated by a partition from the western cella. The northern portico, tetrastyle Ionic, stands at a lower level and gives access to the western cella through a fine doorway. The southern portico, known as the Porch of the Caryatids (see caryatid) from the six sculptured draped female figures that support its entablature, is the temple's most striking feature; it forms a gallery or tribune. Five of the original figures are now in the Acropolis Museum; one, along with an east column, was removed to London by Lord Elgin. The west end of the building, with windows and engaged Ionic columns, is a modification of the original, built by the Romans when they restored the building.