The second of the important sanctuaries at Delphi was dedicated to Athena Pronaea. The remains of its buildings have been excavated to the south-east of the sanctuary of Apollo, in an area which has yielded the earliest known traces of cult worship. A female divinity was worshipped here in Mycenean times, later being replaced by Athena. The sanctuary of Athena stood inside a walled precinct whose main entrance was on its north-east side. The first temple to the oddess was erected in the early sixth century and, unusually, faced south. It was Doric and peripteral, with an altar to the east. Late in the sixth century, a new Doric temple was constructed on the same site, accompanied by a monumental altar to the east of the earlier structure. In the same area altars have been discovered to Zeus Polieus, Athena Erganes, Athena Zosteria, the goddess Eileithyia and Hygeia, the health goddess. To the west of the temple of Athena were two treasuries, one in the Doric order which imitated the treasury of the Athenians (475-470 BC) and one in the Ionic order dedicated by the people of Massalia (Marseilles) late in the sixth century. Still further to the west are the ruins of the Tholos of Delphi, a famous circular building designed by the architect Theodorus and built in 400-390 BC. There were 20 Doric columns round the exterior, and 10 Corinthian columns in the cella. The roof was conical, and the external frieze was ornamented with scenes from the Battle of the Centaurs and the Battle of the Amazons. The frieze of the cella bore sculptures depicting the feats of heroes and assembly of the gods. To the west of the Tholos stood a Doric temple of 370-360 BC and a rectangular building of the fourth century BC whose purpose is unknown to us.