The Castle of San Faustino or Old Castle is located in the municipality of Grosio. It was strategically important for controlling the valley floor, the Mortirolo Pass, and the outlet of the Val Grosina. Naturally protected by the steep rocky slopes of the hill, it is surrounded at its base by the Roasco and Adda rivers. It is easily accessible on foot, beyond the Rupe Magna and the New Castle.
The castle first appears in a 1150 document belonging to the Curia Comense. The church dedicated to Saints Faustino and Giovita likely predates the castle itself, later being incorporated into it and transformed into a chapel. The dedication to these two Brescia martyrs may reflect economic and cultural ties between Valtellina and Valcamonica.
When the Venosta family abandoned the castle, likely around the late 16th century, the church also began a slow but inexorable decline.
Today, only a few ruins of the castle remain, dominated by the Romanesque bell tower of the Church of San Faustino and Giovita. Archaeological excavations have revealed new insights into the castle’s perimeter and historical role. The findings suggest that the northern structures seem to expand as if to embrace the entire hill. The preserved walls allow for the identification of the castle’s outline and related structures. The relatively narrow design, seemingly 'forced' to follow the hill’s morphology, suggests that it served less as a defensive structure and more as a prestigious display of power by the feudal lord who controlled Grosotto and Grosio.
It is likely that the castle was originally much larger than it appears today: a true fortified village modeled after an early medieval castrum, surrounded by a defensive wall that enclosed the entire hill. The oldest construction (6th century AD), identified during the 2000 archaeological excavations, corresponds to a primitive funerary shrine that contained two rock-cut tombs, interpreted as privileged burials.
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.