Abergavenny Castle Abergavenny Castle is a ruined castle in the market town of Abergavenny , Monmouthshire , Wales , established by the Norman lord Hamelin de Ballon in about 1087 . It was the site of a massacre of Welsh noblemen in 1175 , and was attacked during the early 15th century Glyndŵr Rising . William Camden , the 16th century antiquary , said that the castle " has been oftner stain ' d with the infamy of treachery , than any other castle in Wales . " It has been a Grade I listed building since 1952 . Location . The castle is located immediately to the south of the town centre . It was built by the Normans to overlook the River Usk and its valley , and so guard against incursions into the lowland areas south and east of the town by the Welsh from the hills to the north and west . Description . The castle , now in ruins , had a stone keep , towers , and ditch as fortifications . It also housed the family and army of the lord and had cellars , kitchens , a great hall , gatehouse , and a chapel , although it is doubtful whether any of the families treated the castle as their main residence . A curtain wall surrounded the castle . The high , formidable curtain wall , dating from the 12th century , is now the most impressive part of the ruin . A 19th century lodge was built on the top of the motte in the 19th century . History . 11th to 14th centuries . Hamelin de Balun , a Norman lord , had the castle built about 1087 . Protected by a ditch and palisade , the motte was surmounted by a wooden keep . Soon after 1100 , a stone keep was built to replace the wooden structure , and a wooden hall was built on its western side . In the 1160s , Henry Fitzmiles , the son of Miles de Gloucester , 1st Earl of Hereford and lord of Abergavenny , was killed , reputedly by Seisyll ap Dyfnwal of Castell Arnallt . Without a male heir , Henry Fitzmiles ' estate and the lordship , which included lands in upper Gwent and Brecknockshire , as well as the Castle , passed to his daughter Bertha ' s husband , William de Braose . De Braose rebuilt parts of the castle and constructed the curtain wall , parts of which still remain . The castle was then the scene of an infamous massacre . Over Christmas 1175 De Braose called Seisyll and his son Geoffrey to his castle , together with other leaders from Gwent , supposedly as an act of reconciliation . De Braose then had the men killed in the castle ' s great hall , in retribution for the death of Henry Fitzmiles . His action , including taking the men ' s land , resulted in sanctions ; William was " retired " from public life and the castle passed to his son , William . In 1182 Hywel ap Iorwerth , lord of Caerleon , ordered the destruction of Dingestow Castle and had Abergavenny Castle set afire in retribution for the murder of Seisyll . The attacks were made by Seisyll ' s relatives . De Braose was not at the castle when it was burnt , but " most of his men " were taken hostage . The castle was almost entirely rebuilt of local Old Red Sandstone , starting about 1190 , to make it easier to defend . Five towers were built along the curtain walls , and a keep was built . The English and Welsh fought for control of the Welsh Marches and , during this time , possession of the castle alternated between the Welsh and English . In 1215 , the castle was visited by John , King of England . In the 13th and 14th centuries , the castle was expanded by the Hastings family , including the addition of western towers which provided residential chambers . Two towers , one circular and one polygon al , were probably built between 1295 and 1314 by John Hastings , 1st Baron Hastings . This was the same time in which murage taxes were collected from local residents to fund the building of the town walls . Between the late 13th century and the early 14th century , a new wall was built . 15th to 17th centuries . In 1404 , during the rebellion of Owain Glyndŵr , the town of Abergavenny was sacked and burned by Welsh forces . The fortified , or barbican , gatehouse — described by architectural historian John Newman as " unimpressive " — may date from either just before , or just after , that date . No lord took up residence at the castle after the 15th century . During the English Civil War , as the Roundheads neared the castle , Charles I ordered a slighting of the castle to prevent its useful occupation . Most of the castle buildings , including the stone keep , were destroyed . Raglan Castle was similarly damaged . Stone from the site was taken thereafter , to be used for other buildings . 18th and 19th centuries . By the late 18th century , the ruins were starting to attract visitors seeking " picturesque " views , and walks were laid out within the castle walls . In 1819 , Henry Nevill , 2nd Earl of Abergavenny , had a hunting lodge constructed on top of the motte . Newman describes it " an unsympathetically utilitarian structure , enlivened only by thin polygonal shafts at the angles . " A formal public garden , now included on the National Register of Historic Parks and Gardens , was created later in the 19th century by William Nevill , 5th Earl of Abergavenny . It had views overlooking the Usk valley , " picturesque " walks and gardens , and gazebo s . 20th and 21st centuries . The castle and the hunting lodge , now the Abergavenny Museum , have been Grade I and Grade II listed building s , respectively , since 5 July 1952 . Other features , such as the outer wall , have been listed since 2005 . Museum . The castle ' s museum is located in the 1819 hunting lodge on top of the motte . Amongst the museum ' s exhibits are a saddler ' s workshop and a Victorian Welsh farmhouse kitchen .