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:
Sirmione castle was built near the end of the 12th century as part of a defensive network surrounding Verona. The castle was maintained and extended first as part of the Veronese protection against their rivals in Milan and later under the control of the Venetian inland empire. The massive fortress is totally surrounded by water and has an inner porch which houses a Roman and Medieval lapidary. From the drawbridge, a staircase leads to the walkways above the walls, providing a marvellous view of the harbour that once sheltered the Scaliger fleet. The doors were fitted with a variety of locking systems, including a drawbridge for horses, carriages and pedestrians, a metal grate and, more recently, double hinged doors. Venice conquered Sirmione in 1405, immediately adopting provisions to render the fortress even more secure, fortifying its outer walls and widening the harbour.
Thanks to its strategical geographical location as a border outpost, Sirmione became a crucial defence and control garrison for the ruling nobles, retaining this function until the 16th century, when its role was taken up by Peschiera del Garda.