The Basilica of Sts. Vitalis, Valeris, Gervase and Protase is commonly named Basilica di San Vitale. It was built in 400 with funds provided by Vestina, a wealthy dowager, and was consecrated by Pope Innocent I in 401/402. The dedication to St. Vitalis and his family (Saint Valeria, his wife, and Sts. Gervasius and Protasius, their sons) is dated to 412.
San Vitale was restored several times, the most important being the rebuilding by Pope Sixtus IV before the Jubilee of 1475, and then in 1598, 1938 and 1960. The church is currently located several metres under the level of the street (via Nazionale), that it faces.
The portico is the most ancient part of the church, possibly dating back to the 5th century. It was altered at the end of the 16th century. The inscription on the portico, with the arms of Pope Sixtus IV, dates from this time. Pope Pius IX built the staircase to the 5th century portico in 1859.
The church has a single nave, with walls frescoed with scenes of martyrdom, among which a Martyrdom of St Ignatius of Antioch, in which a ruined Colosseum is depicted. The apsis, original of the 5th century, is decorated with a fresco by Andrea Commodi, The Ascent to Calvary.
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.