St Dogmael's Abbey is named after Dogmael, a 6th-century saint said to have been the son of Ithel ap Ceredig ap Cunedda Wledig, and also reputedly the cousin of Saint David.
The abbey was built on or very close to the site of the pre-Norman conquest clas church of Llandudoch. It was founded between 1113 and 1115 for a prior and twelve monks of the Tironensian Order. In 1120 Abbot William of Tiron consented to fitz Martin's request that the priory become an abbey. It remained a daughter house of Tiron, probably until its dissolution. However, in 1138, the village and abbey of St Dogmaels were sacked by Gruffudd ap Cynan's sons.
The earliest surviving remains date from the first half of the twelfth century. It seems that sufficient of the church was built to satisfy the immediate requirements of the monastery, but that the western part for the use of the laity, was not finished. The nave was completed in the thirteenth century, although without the intended aisles. Unusually the church lacks a west doorway, possibly because of the slope of the ground becomes steeper. The square-ended sanctuary was built over a vaulted crypt, possibly a repository for relics of St Dogmael. About the middle of the thirteenth century, the cloister was enlarged northwards; the cloister arcades were rebuilt in stone about the same time. The domestic quarters were extensively rebuilt at the end of the thirteenth or beginning of the fourteenth century. A new infirmary was built, followed by a chapter house. In the fourteenth or fifteenth century, much of the west range was altered to provide improved accommodation for the abbot. A new wing was added for the abbot's guests. The last alteration to the church was the rebuilding of the north transept, with its elaborate fan vaulted roof. This happened in the early sixteenth century, not long before the suppression of the monastery. The lavish design indicates it may have been an individually distinct chapel, possibly built as a memorial to the founder's family, the lords of Cemais.
The abbey was dissolved in 1536, along with hundreds of other houses. By this time, there were only eight monks and the abbot. The majority of the abbey's possessions were leased to John Bradshaw of Presteigne in Radnorshire. He built a mansion, probably within the abbey precinct.
Substantial parts of the church survive, including the western end wall, the north wall, northern transept. The crypt, beneath the former eastern two bays of the presbytery is preserved to the springing of the vault. Fifteenth century floor tiles remain in large areas of the nave.
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.