Ancient Monuments

History on the Ground

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Castell Tomen y Mur

A Scheduled Monument in Maentwrog, Gwynedd

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Latitude: 52.93 / 52°55'47"N

Longitude: -3.9254 / 3°55'31"W

OS Eastings: 270675

OS Northings: 338687

OS Grid: SH706386

Mapcode National: GBR 5Z.MDXW

Mapcode Global: WH55P.NMY5

Entry Name: Castell Tomen y Mur

Scheduled Date:

Source: Cadw

Source ID: 3195

Cadw Legacy ID: ME002

Schedule Class: Recreational

Category: Amphitheatre

Period: Roman

County: Gwynedd

Community: Maentwrog

Traditional County: Merionethshire


A large scheduled area in two parts containing some ten sites. Adjacent and intervening areas are also scheduled. The principal sites are the Roman fort with its vicus and the Roman parade ground and amphitheatre. Within the fort is a Norman motte and probable traces of a bailey.

The motte is built astride the centre of the NW side of the reduced Roman fort (ME078), and may well cover and preserve the gate that must have existed at that point. Ploughing inside the fort has levelled most of the area; a slight bank on the NE of the motte may be the remains of an inner bailey associated with that structure, but irregularities in the ground to the SE of it possibly indicate the site of the Praetorium.

The motte is about 10 m high and is surrounded by a ditch 4 m wide, with a counterscarp bank surmounted by a modern field wall. The top is uneven, with two principal hollows on SE and SW which may represent the sites of original buildings (or possibly robbing). It is slightly oval, measuring approx. 14 m N-S by 19 m E-W.

The monument is of national importance for its potential to enhance our knowledge of medieval fortification practices. It is an important relic of the medieval landscape and retains significant archaeological potential.

Source: Cadw

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