The Temple of Portunus or Temple of Fortuna Virilis ('manly fortune') is one of the best preserved of all Roman temples. Its dedication remains unclear, as ancient sources mention several temples in this area of Rome, without saying enough to make it clear which this is.
The temple was originally built in the third or fourth century BC but was rebuilt between 120-80 BC, the rectangular building consists of a tetrastyle portico and cella, raised on a high podium reached by a flight of steps, which it retains.
The temple owes its state of preservation to its being converted for use as a church in 872 and rededicated to Santa Maria Egyziaca (Saint Mary of Egypt). Its Ionic order has been much admired, drawn and engraved and copied since the 16th century. The original coating of stucco over its tufa and travertine construction has been lost.
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.