The Forum of Augustus is one of the Imperial forums of Rome, Italy, built by Augustus. It was built in 42 BC to commemorate Augustus' victory at the Battle of Philippi over the assassins of Julius Caesar.
The Temple of Mars Ultor stands in the forum. It was inaugurated in 2 BC and it came to function as the focal point of Roman military strategy. For example, Augustus decreed that it should be the meeting place for the Senate when decisions of war were taken. The temple was also the place where young Roman males were ceremoniously given their adult toga, thus becoming eligible for military service, and it was the official departure point for commanders embarking on military service in the empire.
Behind the temple stands a 30 m high tufa wall which is topped with white travertine. It was constructed to separate the Forum from the hill residences behind it and to act as a firewall should a fire start in this densely-populated area of the city. In the 1st century AD Tiberius added two arches to the temple sides in honour of his two sons Drusus the Younger and Germanicus but these have now been lost except for the foundations of one. In the 2nd century Hadrian repaired parts of the building but from the 5th century the building went into decline and blocks began to be re-used in other building projects.
From the 12th century soil was added to the site and the area used for agriculture, however, as the drains were then blocked, a marsh formed until the area was drained in the 16th century.
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.