The original Roman Agora was encroached upon and obstructed by a series of Roman buildings, beginning with the imperial family's gift to the Athenians of a large odeion (concert hall). The Odeon of Agrippa was built by him in around 15 BC, and measured 51.4 by 43.2 metres, rose several stories in height, and – being sited just north of the Middle Stoa – obstructed the old agora. In return for the odeion, the Athenians built a statue to Agrippa at the site of the previous agora; they based it on a plinth recycled from an earlier statue by covering the old inscription with a new one.
After the invasion of the Herulae in AD 267 the city of Athens was restricted to the area within the Late Roman fortification wall, and the administrative and commercial centre of the city was transferred from the Ancient Agora to the Roman Agora and the Library of Hadrian.
During the Byzantine period and the Turkish occupation the area was covered with houses, workshops and churches along with the Fethiye Mosque.
The Tower of the Winds is an octagonal Pentelic marble clocktower that functioned as a horologion or 'timepiece'. It is considered the world's first meteorological station. The structure features a combination of sundials, a water clock, and a wind vane. It was supposedly built by Andronicus of Cyrrhus around 50 BC, but according to other sources, might have been constructed in the 2nd century BC before the rest of the forum.
The Gate of Athena Archegetis is considered to be the second most prominent remain in the site after the Tower of the Winds. Constructed in 11 BCE by donations from Julius Caesar and Augustus, the gate was made of 4 Doric columns and a base of Pentelic marble. It was a monument dedicated by the Athenians to their patroness Athena Archegetis.
The East Propylon is the eastern entrance of the Roman Agora in Athens. Built in 19-11 BCE, it constituted of 4 Ionic columns made of gray Hymettian marble.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.