The temple of Rome and Augustus was erected in the late first century BC. Several architectural elements of the building were found east of the Parthenon and many more were brought here after their discovery elsewhere. Nearby are the irregular tufa foundations (approximately 10.50x13 metres) of a building generally considered to be the Roman temple. Another theory, however, based on the construction technique of these foundations and on depictions of the Acropolis on Roman coins, places the temple east of the Erechtheion.
A small, round edifice, about 23 meters from the Parthenon, was to be the last significant ancient construction on the summit of the rock.
The inscription on the temple's epistyle mentions that the building was dedicated by the city of Athens to the goddess Rome and to Octavian Augustus. Pausanias does not mention the building during his visit to the Acropolis, possibly because it did not present any interest at his time. The small, circular temple had a single row of nine Ionic columns and no interior wall, the entablature and conical roof being entirely of white marble. The fact that the columns imitate those of the Erechtheion may indicate that the temple was built by the same architect who repaired the Erechtheion after it was damaged by fire.References:
Ängsö Castle was first named as "Engsev" in a royal charter by king Canute I of Sweden (r. 1167-1196), in which he stated that he had inherited the property after his father Eric IX of Sweden. Until 1272, it was owned by the Riseberga Abbey, and then taken over by Gregers Birgersson.
From 1475 until 1710, it was owned by the Sparre family. The current castle was built as a fortress by riksråd Bengt Fadersson Sparre in the 1480s. In 1522, Ängsö Castle was taken after a siege by king Gustav Vasa, since its owner, Fadersson's son Knut Bengtsson, sided with Christian II of Denmark. However, in 1538 it was given by the king to Bengtsson's daughter Hillevi Knutsdotter, who was married to Arvid Trolle.
In 1710, the castle was taken over by Carl Piper and Christina Piper. Ängsö Castle was owned by the Piper family from 1710 until 1971, and is now owned by the Westmanna foundation. The castle building itself was made into a museum in 1959 and was made a listed building in 1965. It is currently opened to visitors during the summers.
The castle is a cubical building in four stores made by stone and bricks. The lower parts is preserved from the middle ages. It was redecorated and expanded in the 1630s. The 4th storey as well as the roof is from the expansion of Carl Hårleman from 1740-41. It gained its current appearance in the 1740s.