In 1175 a terrible massacre occurred at the castle. A few years earlier, in 1172 or 1173, the castle was captured from William de Braose by Sitsyllt ap Dwfnwal, a Welsh Chieftain. The castle was restored to Braose by Sitsyllt and the chieftain was invited to a feast to celebrate its return. But instead of this being a friendly meeting Braose had Sitsyllt ap Dwfnwal and his guests cruelly murdered.
The castle has had a chequered history being attacked many times and changing hands. In 1215 the castle was captured from King John's forces by LLewellyn, the Prince of Wales. In 1403/4 it was attacked and destroyed by Owain Glyndwr. Again in 1646 during the English Civil War the castle was subject to attack. This time the castle was totally destroyed so it could not be used as a fortification again. The stones were robbed to provide building material for the nearby town.