The olive-wood statue Athena Polias resided in the west part of the central chamber and faced east. It is believed that the statue was in real life-size. This is based on several sources describing it to be mobile, in that sense it was evacuated from Acropolis in 480 BC before the Persians came, and functioning as a mannequin with special clothing in festival rituals. There is disagreement whether the statue was seated or standing, but it is likely that the ancient statue stood rigidly upright, with a gold phiale in one hand and an owl in the other.

Several inscriptions inventory an impressive array of ornaments somehow attached to the statue: “a diadem [or crown] which the goddess wears, the earrings which the goddess wears, a band which the goddess wears on her neck, five necklaces, a gold owl, a gold aigis, a gold gorgoneion, and a gold phiale [a shallow libation bowl] which she holds in her hand.”

It is certain that the statue wore cloth as well as gold. Every year, the statue was dressed in a new saffron-colored woolen robe, or peplos, (measuring perhaps 5 by 6 feet) woven by selected Athenian girls and women and principally decorated (in contrasting purple) with inwoven scenes from the battle between the gods and giants, the savage sons of Earth (Gaia) who tried to overthrow the Olympians.

Jeffrey M. Hurwit: "The Acropolis in the age of Pericles"
Wikipedia: Athena
The Theoi Project: Panathenaia
Erechtheion.org