Aerial view of Oystermouth Castle showing allotments gardens. Click on image to enlarge.
It is probable that William de Londres I founded the castle at Oystermouth in 1107 when Henry Beaumont conquered Gower. The primary castle of earth and timber was surmounted by a stone keep around 1138 and in the early thirteenth century an extended central block (incorporating the earlier keep) was added. The northwest block and part of the west range appear to have been added in the mid thirteenth century and in the late thirteenth century the gatehouse and curtain wall were constructed. In the early fourteenth century a chapel was added and other additions, including the southern offices and latrine turrets, were made before the end of the medieval period. There are traces of wall paintings in the southern recess of the chapel and on an area of plaster beneath the vault. These consist of a repetitive diamond pattern containing flowers and coats of arms. Traces of pigment have also been noted in the south-east angle of the recess.