Ancient Monuments

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Roman Road on Mynydd Illtyd, south-western section

A Scheduled Monument in Glyn Tarell, Powys

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Latitude: 51.9203 / 51°55'13"N

Longitude: -3.512 / 3°30'43"W

OS Eastings: 296110

OS Northings: 225724

OS Grid: SN961257

Mapcode National: GBR YJ.P7G8

Mapcode Global: VH5FG.2ZPR

Entry Name: Roman Road on Mynydd Illtyd, south-western section

Scheduled Date: 30 October 1996

Source: Cadw

Source ID: 3458

Cadw Legacy ID: BR224

Schedule Class: Transport

Category: Road

Period: Roman

County: Powys

Community: Glyn Tarell

Traditional County: Brecknockshire


The monument consists of the remains of a road, dating to the Roman period (1st to 5th century AD) period. This section of road forms part of Sarn Helen, the route from Neath to Caernarfon, and connects Coelbren fort (20km to the SW) and Brecon Gaer (5km to the NE). The monument comprises two well-preserved sections of causeway extending across open moorland for 420m SW to NE. The agger is a well-defined grassed mound averaging about 8m wide with rushes growing along the line of the side ditches and several quarry depressions flanking it, especially to the S. A section was cut through the road by Jones in 1957 which revealed a cambered causeway with shallow side ditches, overall about 5.5m wide. The agger was about 4.3m wide and up to 0.6m high, and was composed of a core of sandstone, with larger pieces towards the base, capped with gravel.

The monument is of national importance for its potential to enhance our knowledge of Roman military organisation/medieval transport systems. The monument forms an important element within the wider context of the Roman occupation/medieval settlement of Wales and the structure may contain well preserved archaeological evidence concerning chronology, layout and building techniques.

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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