Oystermouth Castle

Oystermouth Castle is a ruined castle of rubble limestone, with a roughly triangular plan. At the south end stands a gatehouse flanked by curtain walls that angle outward to enclose an inner court. On the north side, occupying the highest ground, is a Norman keep with an added range on its north side, together forming a double-depth central block. A northwest block abuts this central block, while a west block is separated from it by a narrow passage. On the east side of the central block is a high chapel block dating from the 14th century.

The Gatehouse and Curtain Walls

The two-storey gatehouse is flanked by the curved walls of former drum towers. Each tower has a blocked pointed doorway in the lower stage and beam sockets indicating an upper floor. The east curtain wall has a battered base and an added garderobe turret with a return at the north end. Set back from the angle is the later chapel block, which features cusped lancets in the lower storeys and a three-light window with intersecting tracery in the upper-storey chapel. The chapel block has an embattled parapet with arrow slits. Its north wall contains two two-light windows flanking a central square buttress, with a further blocked lancet lower on the right.

The central block projects northward and has a battered base with blocked east windows. In its north wall are putlog holes and, in the lower storey, three narrow splayed lancets; three wider lancets pierce the middle storey, while the upper storey is stepped in and has two windows. The adjoining northwest block is obscured by vegetation but has a garderobe shaft at its centre. In its west wall, the head of a low arch is visible at ground level.

The west block has a shallow projecting garderobe turret at the northwest end and a blocked window to its right. It features a string course below parapet level and putlog holes. Small square-headed windows light two cellars inside, beneath which the wall is battered. There is a butt joint between the west block and the west curtain wall, which is faceted and has a single projecting garderobe turret added in the 14th or 15th century.

The Gatehouse Interior

The entrance passage of the gatehouse is tunnel-vaulted and retains a single portcullis slot. On the inner side, the main gateway has a segmental arch in three orders that dies into the responds. Above this is a formerly lintelled window. Segmental-headed doorways flanking the main gateway lead to steps down to the lower stages of the drum towers, where there are blocked doorways. To the right of the right-hand doorway, an external stone stair leads to the upper storey. At the top of the stair, an arched doorway on the right leads to a small chamber with a narrow window in its west side.

The portcullis chamber has a window seat on the north side under a pointed rear arch. In the west wall is a fireplace with a projecting segmental hood. Corbels supporting the former roof are retained. On the northeast side is a short tunnel-vaulted passage to a newel stair on the east side of the gatehouse that leads up to the wall walk. The newel is partly renewed in concrete. The wall walk continues on both curtain walls.

Service Buildings Against Curtain Walls

Both curtain walls retain evidence of two-storey service buildings built against them in the late medieval period. On the east side, possibly a barracks, are two segmental-headed fireplaces indicating a two-storey building. On the west side, the structure has two doorways to the court, although no jambs are now visible. Against the curtain wall are two segmental-headed fireplaces at ground floor level. In the northwest gable end is a larger fireplace with projecting segmental head, indicating a kitchen. At the northwest end is a small pointed doorway to a garderobe in the curtain wall.

The Central Block (Keep and Extensions)

The central block comprises the basement of the mid-12th-century keep (although the openings are all later), which had a first-floor hall. This was extended in the early 13th century by an additional gabled range on the north side to create a double-depth hall block. A storeyed porch on the west side of its front was added in the early 14th century and is probably contemporary with the chapel block.

The porch has a doorway with a pointed arch reached by stone steps, leading to a tunnel-vaulted entrance vestibule which has a portcullis slot. The south wall of the keep has a round-headed arch of an inserted doorway later blocked with a narrow loop inserted inside it; further to the right is a lancet window. The porch leads through a pointed-arch doorway to the basement below the first-floor hall. This basement has window seats in the south and east walls. In the north wall is a fireplace flanked by corbels of a former projecting hood. At the west end is a doorway to the later range added on the north side. Directly above it is another doorway. The north and south walls contain former beam sockets. Of the great hall on the first floor, little detail is now visible. In the west wall are first-floor and gable windows, and beam sockets suggesting a screened passage and minstrel's gallery at this end.

A projecting stair turret in the northwest corner was an integral part of the 13th-century extension of the keep. It has a newel stair that is closed to the basement of the keep and north range, but communicates between the hall and a lower mural stair in the west wall of the added north range that leads down to a vaulted cellar beneath the north range. Around the newel stair is a mural passage communicating between the lower storey of the keep and the northwest block.

The North Range

The north range of the central block has, in the south wall, a fireplace with a raked hood projecting on corbels. Window seats are in the east and north walls. Against the west wall are stone steps, inserted in the post-medieval period, leading to a tunnel-vaulted cellar. At the bottom of the steps, the crown of an arch is visible in the north wall. The upper storey solar has two window seats in the north wall and a doorway at the west end, plus the embrasure of a window in the east wall.

The Guardroom

On the west side of the original keep is a guardroom, which is contemporary with the porch. It is two storeys under a lean-to roof, the upper storey having been a room entered from the great hall. In the south wall facing the court is a pointed doorway with a draw bar socket. In the west wall are two slits, and the embrasure of at least one window survives above.

The West Block

The narrow passage between the central and west blocks has a segmental arch at the south end. The west block is built in two phases. The south range has two tunnel-vaulted cellars. In the southernmost cellar, the vault partly obscures the head of a window, showing that the present vault is secondary. Stone steps against the east wall lead up to the ground floor. This level has putlog holes visible in the north and south walls. In the west wall is a fireplace with corbels of a former hood. To the left of the fireplace at low level is the crown of a pointed arch. To the right of the fireplace is a low recess and further right a segmental-headed fireplace. The south wall has a large pointed-arched window. In the north wall, a similar window was cut down to ground level to make a door when a further range was added on the north side.

The batter at the base of the original north wall of the block is visible in the added north range. This added range is three storeys. The lower storey has, in the west wall, a central window seat (the window is infilled) with a fireplace to the left and a pointed doorway to the right leading to a garderobe. In the north wall is a doorway to the lower cellar of the northwest block. In the middle storey west wall is a central window seat with a fireplace to the left and doorway to the right, as in the lower storey. Access is gained through a pointed doorway in the east wall, to the right of which are a pointed window and stone steps to a segmental doorway into the lower storey. In the upper storey west wall is a central fireplace with a raked hood projecting on corbels. Attached to the east side of the range is a two-storey projection with a roof of stone slabs, consisting of a cistern in the lower storey and two segmental-headed windows in the upper storey.

The Northwest Block

The passage between the central and west blocks leads to the northwest block, which is two storeys above two superimposed vaulted cellars. Originally two storeys with one cellar, the block was heightened in the 14th century to create a new upper storey while the original lower storey was converted to another cellar. The passage leads into the upper cellar through a pointed doorway with a draw bar socket. Inside, the vault has an added central stone pillar. There are putlog holes in the north and south walls, two windows in the north wall, and a blocked opening in the east wall. A garderobe in the northwest corner has a narrow slit. The cellar does not extend the full length of the block as there are two cisterns at the west end.

The lower storey of the northwest block is reached by mural passage from the central block, or by a pointed doorway in the west wall of the range added on the north side of the central block. It has square-headed windows of the first phase at low level and later square-headed windows, together with a fireplace in the south wall, at a higher level. Of the upper storey, little survives. At the east end was a watchtower, the chamber of which retains a hooded fireplace; from here, steps lead up over the northwest angle of the central block to the former parapet.

The Chapel Block

The chapel block is on the east side of the central block and is of coursed limestone. It is three storeys with projecting turrets on the southwest, southeast, and northeast angles, and central buttresses. The southwest turret houses a newel stair. The upper-storey chapel has two-light windows with hood moulds in its side walls.

Inside, the basement has a window seat in the east wall and a wide segmental-headed fireplace in the north wall with a blocked window and seat to its left. In the south wall, the main doorway is offset to the west side. At the east end is a doorway to a garderobe; on the west side is a doorway to the stairway.

The apartment in the middle storey has a window seat in the east wall. In the north wall is a doorway on the right leading to a garderobe in the northeast turret, and a blocked window and seat to the left. The south wall has a fireplace with a shallow cambered head, and to its right a window seat above the main lower-storey doorway.

The upper storey was the chapel, which has two two-light windows in the side walls and a three-light east window. The chapel was entered from the great hall. The north and south walls have recesses said to have been confessionals. At the east end is a piscina with a cusped head. The east wall has corbels in the angles. A doorway in the southwest angle leads to the mural stair, which continues up to a gallery walk at eaves level.