Aqua Anio Novus ('New Anio aqueduct') was an ancient Roman aqueduct. Like the Aqua Claudia, it was begun by emperor Caligula in 38 AD and completed in 52 AD by Claudius.
The aqueduct was split into two channels above Tivoli and combined again near Gericomo. From its filtering tank near the seventh milestone of the Via Latina it was carried on the arches of the Aqua Claudia, in a channel immediately superposed on the latter. It terminated at a great tank on the Esquiline Hill near the temple of Minerva Medici.
As the water was prone to be turbid, Trajan made use of additional sources from the two uppermost of the three lakes formed by Nero for the adornment of his villa at Subiaco, thus lengthening the aqueduct to 58 miles and 700 paces. The lakes were created by dams in the river, and were the tallest of any built by the Romans. They were swept away by the river in the Medieval period.
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.