You are hereOystermouth Castle
Oystermouth Castle set in the Gower Peninsula was first built in 1106 by William de Londres of Ogmore Castle. In 1116 the Welsh rove him out and burnt the castle down. It was destroyed again by the Welsh in 1137 after being rebuilt. The Gower Lordship was given to John de Braose who also owned Swansea Castle after the area had become more stabilized by 1220. It was the wealthy descendents of de Braose that would rebuild Oystermouth as a stone castle.
Oystermouth was very important and served as the main residence for the de Braose dynasty until they moved on in 1331.
By the end of the medieval period the castle was falling into ruin and by 1650 was described as "an old castle of no use...".
The Earl of Cawdor made some refurbishments in the 19th century and Oystermouth is today a very picturesque.
The castle is reportedly haunted by a White Lady that is usually seen crying and having a series of wounds upon her back. One witness account I found described how a man taking his dog for a walk around the castle approached a tree after his dog had ran away from it in fear. Behind the tree he saw what he thought was a white sheet, that then rose and took the form of a woman in a white robe, before dissolving into mist.
Another account shows a family having a picnic. The children who had been playing come back to their parents saying they had seen a scary lady in a white robe. The father goes to investigate and sees the White Lady by a tree. She turns from him, revealing her naked lacerated back then vanishes.
Rumor would suggest that she was a medieval prisoner held at the castle who was whipped to death. A whipping post is still in the castles dungeon.
It is believed that the ghost of the "Woman in White" dates from Medieval times and had been a prisoner of Oystermouth Castle who had been literally whipped to death on the Whipping Post which still stands in the castle's large dungeon.