But it was the Acropolis which was the chief centre of the architectural splendour of Athens. After the Persian wars the Acropolis had ceased to be inhabited, and was appropriated to the worship of Athena and to the other guardian deities of the city. It was covered with the temples of gods and heroes; and thus its platform presented not only a sanctuary, but a museum, containing the finest productions of the architect and the sculptor, in which the whiteness of the marble was relieved by brilliant colours, and rendered still more dazzling by the transparent clearness of the Athenian atmosphere. It was surrounded with walls, and the surface seems to have been divided into terraces communicating with one another by steps. The only approach to it was from the Agora on its western side at the top of a magnificent flight of marble steps, 70 feet broad, stood the Propylaea, constructed under the auspices of Pericles, and which served as a suitable entrance to the exquisite works within. The Propylaea were themselves one of the masterpieces of Athenian art. They were entirely of Pentelic marble, and covered the whole of the western end of the Acropolis, having a breadth of 168 feet. The central portion of them consisted of two porticoes, of which the western one faced the city, and the eastern one the interior of the Acropolis, each consisting of a front of six fluted Doric columns. This central part of the building was 58 feet in breadth, but the remaining breadth of the rock at this point was covered by two wings, which projected 26 feet in front of the western portico. Each of these wings was in the form of a Doric temple. The northern one, or that on the left of a person ascending the Acropolis, was called the PINACOTHECA, from its walls being covered with paintings. The southern wing consisted only of a porch or open gallery. Immediately before its western front stood the little temple of Nike Apteros already mentioned.