One of the major 5th-century BCE marble buildings on the Acropolis is known as the Erechtheion, though this name (Erechtheos was a mythical king of Athens) has been challenged. It housed the venerable wooden statue of Athena Polias ('guardian of the city'), so old that it was said to have fallen from heaven, and so formed the focus of the cult of Athena. The building has an unusually complex plan. Pausanias' account of the 2nd century CE, moreover, shows that it was required either to house or be adapted to numerous sacred relics, including a well of salt water, an olive tree, the marks of a thunderbolt or Poseidon's trident, the tomb of Kekrops and the sanctuary of Pandrosos. Its steeply sloping site also created drastic variations in building levels. The original plan was apparently for an amphiprostyle temple with six columns at either end. The west porch was, however, replaced by an enclosed chamber with four Ionic columns engaged in its west façade. To compensate, a large prostyle porch with six Ionic columns was added to the west end of the building's north side , and, to balance this, a smaller prostyle porch with six caryatids was added to the west end of its south side. The building is of Pentelic marble, except for its frieze, which is of grey Eleusinian stone with figures in white marble attached by pins. Its various architectural mouldings, column capitals and upper shafts are elaborately carved. Building work may have begun in either the 430s or 420s BCE, and was certainly suspended for a while: a large inscription from the year 409/408 BCE preserves a detailed record of the state of the building, finished almost to its roof, prepared by the board of commissioners responsible for its completion. The accounts which follow record the prices paid for completing the upper parts of the building, producing the sculpture and the finishing touches, such as fluting the columns. Athenian citizens, resident aliens and slaves worked side by side on the temple. Architects are named, but it is unclear who designed the building as a whole.Grove Dictionary of Art
