Ancient Monuments

History on the Ground

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Castell Nos

A Scheduled Monument in Maerdy (Y Maerdy), Rhondda, Cynon, Taff (Rhondda Cynon Taf)

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Latitude: 51.6907 / 51°41'26"N

Longitude: -3.4989 / 3°29'56"W

OS Eastings: 296488

OS Northings: 200172

OS Grid: SN964001

Mapcode National: GBR HH.4QM8

Mapcode Global: VH5GM.9RMR

Entry Name: Castell Nos

Scheduled Date: 24 July 1979

Source: Cadw

Source ID: 3886

Cadw Legacy ID: GM408

Schedule Class: Defence

Category: Motte

Period: Medieval

County: Rhondda, Cynon, Taff (Rhondda Cynon Taf)

Community: Maerdy (Y Maerdy)

Built-Up Area: Ferndale

Traditional County: Glamorgan


The monument consists of the remains of a defensive motte probably dating to the medieval period. It is unusual in that instead of creating an earthen mound (motte) to defend, a natural pennant sandstone outcrop has been artificially scarped and steepened. The outcrop is set above the precipitous eastern slope of the head of the Rhondda Fach Valley. It commands the Glamorgan side of the watershed between the Rhondda area and Brecon. It thus controls one of the major routes into the Glamorgan uplands from the north.

At the northern end of the outcrop there is a ditch approx. 3m below the break of scarp which curves round in a 'half moon' shape and this protects the less steep northern approach. In the centre of the ditch is a masonry foundation 3m square, possibly connected with a drawbridge abutment. There is a second slight ditch, running concentric to the first, 27m beyond it. It is an unusual site and may have been used as a castle mound built in the period following the seizure of Glyn Rhondda by de Clare in 1246.

The monument is of national importance for its potential to enhance our knowledge of medieval defensive practices. The monument is well-preserved and an important relic of the medieval landscape. It retains significant archaeological potential, with a strong probability of the presence of both structural evidence and intact associated deposits.

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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