 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 nunnery . Cannington is also the site of the 13th @-@ century Gurney Manor and Blackmoor Farmhouse , which was built around 1480 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 Charlynch near Spaxton are still standing only blue lias rubble walling standing on a conical earthwork with a ditch approximately 820 feet ( 250 m ) in circumference are the only remains of Stowey Castle which was destroyed in the 15th century , which may have been as a penalty for the local Lord Audley 's involvement in the Second Cornish Uprising of 1497 led by Perkin Warbeck . 
