When the architect Mnesicles received the commission to design the new Propylaia to replace the ones damaged in the Persian storming of the Acropolis, he had to make allowance for the temple of Athene Nike that already occupied the rocky outcrop just to the south of the old Propylaia. As we have seen, this temple was planned in Egyptian feet of 300 mm. This fact may have induced Mnesicles to choose the same module for his Propylaiain Mnesicles design the temple and the Propylaia were merged into a single conception. The temple of Athena Nike was a natural complement to the Propylaia, since from its platform one could observe at a distance anyone approaching the citadel.
The Temple of Athena Nike was the first structure of the Acropolis to appear to the sight of the ancient visitors mounting the road that snaked its way up the western side of the citadel. After they passed the last turn in the road, the Propylaia emerged to their view. It consisted of six Doric columns 8.81 meters (29 1/3 Egyptian feet) in height. These columns were a sort of preview of the Parthenon within its outer colonnade, just as the earlier propylaia, with their two Doric columns, were an image of the temple in antis within the outer colonnade of the Old Temple of Athena. The ancient visitors wishing to enter the Acropolis were funnelled into a narrow passage between the two central columns. This passage was marked by six Ionic columns, three on either side, 10.21 [10.20] meters (34 Egyptian feet) in height. These columns formed the central isle of a hallway whose dimensions were 18.12 [18.15] x 28.50 m. (60½ x 95 Egyptian feet). After walking through this narrow passageway, the visitors found themselves faced with five steps and five doorways. The dimensions of the middle of these five doorways are as follows:
Though these doors the visitors emerged in a smaller hallway with six Doric columns, 8.53 m in height (8.55 m = 28½ Egyptian feet). North of the narrow passageway was a room in the shape of a small temple in antis, with three Doric columns between the antae, 5.85 m. (19½ Egyptian feet) in height.