Bridgwater Castle Bridgwater Castle was a castle in the town of Bridgwater , Somerset , England . Early history . The castle was built in 1202 by William Brewer , like several other castle - builders of the period , an exceptionally wealthy man . He was granted the lordship of the Manor of Bridgwater by King John in 1201 , and founded Bridgwater Friary . Before the building of the castle , Bridgwater was much smaller , but after the granting of the charter by King John for the construction of the castle , charters for the creation of a borough and a market rapidly followed , effectively creating the heart of a new town . Initially Bridgwater faced competition from the established nearby port of Downend , but the new settlement rapidly became dominant . William Brewer died in 1226 and his son , also called William , died in 1232 ; after his death , the castle passed to the king the following year , after which it was used as a store and prison . In 1242 repairs were ordered to its motte and in 1246 to the towers . In 1248 ownership passed to Maud de Braose , Baroness Mortimer the wife of Roger Mortimer , 1st Baron Mortimer , and the castle was involved in the Second Barons ' War . In the Despenser War of 1321 , Edward II undertook a campaign against the Mortimers , by then a potentially rebellious Marcher Lord family . After the short war , the crown again occupied Bridgwater until 1326 to prevent Roger Mortimer , 1st Earl of March using it as a base for operations if he should escape from custody or return from exile in France . Roger Mortimer did return from France with Edward ' s wife , Isabella ; once they had seized the throne , the castle was returned to the Mortimer family but its upkeep was neglected and part of the moat was filled in . Only St Mark ' s Chapel and a barn were repaired , until the 1380s and 1390s when the towers , gatehouse and barbican were reinforced . By 1450 private houses had been built within the walls and its military value was reducing . Civil war and the Monmouth Rebellion . Some of the external walls of Bridgwater Castle were demolished in the early 1630s by the then owner Henry Harvey . In 1642 , however , the English Civil War broke out between supporters of Charles I and Parliament : the town and the castle were still seen as having value and a garrison was established by the Royalists under Colonel Francis Wyndham , a personal acquaintance of the King . Wyndham ' s wife , Lady Crystabella Wyndham , infamously fired a musket shot at Cromwell but missed and killed his aide de camp . Eventually , with many buildings having been destroyed in the town , the castle and its valuable contents were surrendered to the Parliamentarians on 21 July 1645 . The castle itself was deliberately destroyed the following year , while in 1651 Colonel Wyndham made arrangements for Charles II to flee to France following the Battle of Worcester . Although Robert Blake was born in Bridgwater and became one of the most important military commanders of the Commonwealth of England and one of the most famous English admirals of the 17th century , he is not thought to have been involved in the fighting in the town . During the Monmouth Rebellion of 1685 rebel troops were hemmed in at Bridgwater on 3 July , and were ordered to refortify the town , prior to the Battle of Sedgemoor . Rebuilding of the site . During the later part of the 17th century John Harvey built a mansion on the summit of the site . The rest of the land was acquired by James Brydges , 1st Duke of Chandos who developed an industrial centre in the town . Much of the site was built on in the 1720s to create the Georgian Castle Street . Parts of the castle wall , water gate and undercroft still survive . The mansion was later demolished and the site laid out as King ' s Square . Recent history . In 2008 , during sewer renovation work , a section of the curtain wall of the castle and a tunnel used to transport goods from the port were discovered . Architecture . Bridgwater Castle was a substantial structure built in Old Red Sandstone , covering a site of 8 or 9 acres ( 32 , 000 to 36 , 000 m² ) . A tidal moat , up to wide in places , flowed about along the current streets of Fore Street and Castle Moat , and between Northgate and Chandos Street . The moat was filled from Durleigh brook , a tributary of the River Parrett . Unusually , the main entrance opposite the Cornhill was built with a pair of adjacent gates and drawbridge s . In addition to a keep , located at the south - east corner of what is now King Square , documents show that the complex included a dungeon , chapel , stables and a bell tower . Built on the only raised ground in the town , the castle controlled the crossing of the town bridge . A thick portion of the castle wall and water gate , which are grade II * listed can still be seen on West Quay , and the remains of a wall of a building that was probably built within the castle can be viewed in Queen Street . The foundations of the tower forming the north - east corner of the castle are buried beneath Homecastle House .