The ancient Agora of Argos started to be organized during the 5th century BC. in the south of the city, on the crossroads from the Heraion of Argos, Corinth and Tegea. The architectural programme was completed at the end of the 4th century BC. During the Classical and the Hellenistic periods, the Agora was surrounded by porticos and buildings which can hardly be distinguished at present under the later architectural phases.
During the Roman times, many of the existing buildings were altered in shape and function, mostly into shops and fountains when, in the 2d and 3d century A.D. a general remodeling of the site took place. Later, during the 4th century A.D., a last monument of Paganism was built, a hearth surrounded by boundary steles from the enclosure (peribolos) of an 'heroon' of the Archaic period dedicated to the 'Seven against Thebes'. The invasion of the Goths, in 395-396 A.D. accelerated the destruction and the disappearance of the monuments of the Agora.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.