Saint-Riquier gained fame for its abbey, founded about 625 by Riquier (Richarius), son of the governor of the town, when the town was within Austrasia in the Merovingian Kingdom. It was enriched by King Dagobert I and prospered in the early 9th century Carolingian Empire under the abbacy of Angilbert, son-in-law of Charlemagne. In the year 881 Northmen burned the abbey and destroyed much of what was Centula.
The monastery was rebuilt in the Middle Ages on a smaller scale. The abbey was part of the diocese of Amiens in Ponthieu. The early counts of Ponthieu originally were styled advocatus of the abbey of Saint Riquier and 'castellan' of Abbeville. The counts of Ponthieu enrolled their younger sons who were going into religious vocations at the abbey. Count Enguerrand I placed his sons, Fulk, later abbot of Forest-l'Abbaye, and Guy, later the bishop of Amiens, in Saint Riquier for their education. Their teacher was abbot Enguerrand 'the Wise' (d. 9 December 1045), under whose rule Saint Riquier enjoyed its golden age.
Today's 18th century buildings are occupied by an ecclesiastical seminary. The present church, built in the 13th and 14th centuries, is a magnificent example of Flamboyant Gothic architecture, and has a richly sculptured front on the west, surmounted by a square tower. In the interior the fine vaulting, the Renaissance font and carved stalls, and the frescoes in the treasury are especially noteworthy. Among other valuable relics, the treasury possesses a copper cross said to be the work of Saint Eloi (Eligius).
In 1536 Saint-Riquier repulsed an attack by the Germans, during its defense the women especially distinguishing themselves. In 1544 it was burned by the English, an event that marks the beginning of its decline.
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.