Ancient Monuments

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Penrhos Mound & Bailey Castle

A Scheduled Monument in Llantilio Crossenny (Llandeilo Gresynni), Monmouthshire (Sir Fynwy)

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Latitude: 51.8147 / 51°48'52"N

Longitude: -2.8582 / 2°51'29"W

OS Eastings: 340933

OS Northings: 213245

OS Grid: SO409132

Mapcode National: GBR FD.WTXW

Mapcode Global: VH799.DNT6

Entry Name: Penrhos Mound & Bailey Castle

Scheduled Date:

Source: Cadw

Source ID: 2977

Cadw Legacy ID: MM097

Schedule Class: Defence

Category: Motte & Bailey

Period: Medieval

County: Monmouthshire (Sir Fynwy)

Community: Llantilio Crossenny (Llandeilo Gresynni)

Traditional County: Monmouthshire


The monument comprises the remains of a motte and bailey castle, a military stronghold built during the medieval period. The site stands in a commanding position on a ridge top, with extensive views to the N and W. The motte is around 5m high with a flat top 13m in diameter and has very steep sides. A ditch surrounds the base of the motte. Its dimensions vary around its circumference but it is a maximum of 2.5m wide and 2m deep, and there is a narrow causeway crossing it on the NE side. Outside the ditch, surrounding the motte, is a roughly oval area of flat ground enclosed by an outer ditch. This flat area is 12m wide to the NE of the motte and 7m to the S. At the outer edge of the flat area there is a steep drop, of up to 3m, down to the outer ditch. A narrow bank surrounds the outer ditch, this is up to 1.5m high, and beyond it on the W side the ground slopes steeply away. The bailey area extends from the outer ditch to the N, but is no longer visible. The castle was built by John of Monmouth in 1248, but was seized three times by William de Cantilupe the younger, and finally 'thrown down' by William in 1253.

The monument is of national importance for its potential to enhance our knowledge of medieval defensive organisation. The well-preserved monument forms an important element within the wider medieval context and the structure itself may be expected to contain archaeological information relating to chronology, building techniques and functional detail.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.

Source: Cadw

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