 There are 53 Grade I listed buildings in Sedgemoor , 14 of which are in Castle Street , Bridgwater . In 1834 , Castle Street was built on the site of the demolished Bridgwater Castle , as homes for the merchants trading in the town 's port . Outside the town of Bridgwater , the largest concentration of Grade I listed buildings are in the village of Cannington , where the 12th @-@ century Cannington Court and 14th @-@ century Church of St Mary were both associated with a Benedictine <unk> . Cannington is also the site of the 13th @-@ century <unk> Manor and <unk> Farmhouse , which was built around <unk> with its own chapel . Although 11th @-@ century churches such as the Church of St Michael at Brent Knoll and the Church of St Mary at <unk> near <unk> are still standing only blue <unk> rubble <unk> standing on a conical <unk> with a ditch approximately 820 feet ( 250 m ) in <unk> are the only remains of <unk> Castle which was destroyed in the 15th century , which may have been as a penalty for the local Lord <unk> 's involvement in the Second Cornish Uprising of <unk> led by <unk> <unk> . 
