Ruined Undercroft at St Mary's Abbey

Cadw's description

Location

Located to the S of the Chapter House and E of Margam Orangery.

History

Robert of Gloucester, Earl of Glamorgan, granted lands for a Cistercian Abbey at Margam in 1147. Most of the nave of the original C12 abbey church survives and is now the parish church. The rest of the abbey church and the remaining monastic buildings were rebuilt in Early English style in the early C13, probably in 1203-13 under Abbot Gilbert. The undercroft belongs to this phase. It supported a storey above, probably a bridge leading to the monks' dormitory at right angles to the W. Alternatively, the upper storey could have been part of the dormitory or even an infirmary, although the latter is likely to have been in a more isolated position.

Margam Abbey was dissolved by the crown visitors of Henry VIII in 1536-7 and the monks evicted. By 1540, Sir Rice Mansel (1487-1859) of Oxwich and Old Beaupre had acquired most of the former monastic lands. He built an impressive Tudor house, incorporating some of the monastic remains into the service areas.

Exterior

Three-bay vaulted structure orientated E-W of roughly coursed stone with quoins. Arcade of 3 pointed arches surviving to just above apex level, but the E arch of the N side is no longer extant. Low impost band to arches, chamfered to underside. Pilasters to fronts of piers. Wide arches to E and W ends, the dressings no longer surviving. The E piers are built into short N-S walls with quoins, possibly demarcating a corridor or range beyond. A break in this wall further N suggests a doorway. Large pier or wall fragment against N side of NW pier, while a short wall joins the W side of the SW pier. Quadripartite ribbed vaults survive to the W and central bays. Low scalloped corbels between the vaults support chamfered ribs.

Reason for designation

Listed grade I as a rare survival in S Wales of a medieval monastic building. Group value with Abbey Church of St Mary and chapter house.

Scheduled Ancient Monument GM005 (NEP).