Historic Landscape Characterisation

Trawsfynydd - Area 17 Tomen y Mur relict Roman landscape (PRN 18283)

© Crown copyright. All rights reserved, Gwynedd Archaeological Trust, 100017916, 2005

Historic background

The Roman fort at Tomen y Mur lies at the cross roads of four Roman roads: where the road from Caernarfon and Pen Llystyn (RRX95, Hopewell, 2004) becomes the road to Caer Gai (RR68), which crosses (at a point south of the fort) the road south to Brithdir (RR69b) and north to Canovium (RR69a) (Hopewell, 2004). It is situated on the brow of a low spur, c 280m OD, which commands good views of the local area. Three main periods of occupation are visible on the site (Jarrett, 1969, 112). Fragments of the bath-house, which lies south-east of the fort were examined in the mid-19th century, while the two main structural phases were examined by excavation in 1962. It was probably originally built in AD 77 or 78 as a result of Agricola's campaign, its earthen defences enclosing an area of 1.7 hectares. Under Hadrian, it was reduced in size (by bringing the north-west line of defences ‘into’ the earlier fort) and rebuilt in stone, a process recorded in a series of 10 centurial stones discovered in the 19th century (some now in the National Museum). The fort does not seem to have been garrisoned for long after the rebuilding and may have been abandoned by the middle of the 2nd century AD, although a 5th-century gravestone found nearby indicates some form of continued settlement. The fort is referred to as Mur y Castell in the Mabinogion (see section above), the name Tomen y Mur deriving from the motte the most prominent feature on the site) for which the later (smaller) fort provided a ready made bailey (the motte lies over its north-west defences). Very little is known of the history of the motte beyond the fact that William Rufus campaigned there in 1095. The fort is surrounded by an extensive complex of ancillary earthworks, described below. Around the Roman practice camps at Dolddinas, a series of nine fields along with a set of buildings show early 19th-century encroachment on to the Migneint Common (area 15). There is a similar (albeit larger) example of similar encroachment at Dolbelydr to the north west.

Key historic landscape characteristics

Relict Roman archaeology

The earthworks as they stand today (and are visible on the photograph) constitute one of the most impressive and interesting Roman sites in Britain, not only because of their sequence of construction, reduction and medieval reuse, but because the fort is surrounded by an exceptionally complete and well preserved series of ancillary buildings: bath-house, mansio (guesthouse), practice earthworks, leats, roads and burial monuments. The rampart of the fort is possibly best-preserved near the former north-east gate (near where the later, ruinous farmhouse stands). Here it is fronted by a modern wall built from well-cut, undoubtedly Roman, stone. Between here and the motte is a levelled platform on which the stone-built headquarters building (principia) stood. The motte, surrounded by a sharply cut ditch, covers the narrow stone bank which was the north-western rampart of the reduced fort. The rounded earth banks of the original, larger fort are still visible to the west and south-west. The double guardchambers and central pier of the south-west gateway, as well as the stone blocking (probably original) exposed by 19th century excavations, are still clearly visible. Outside and to the north of the fort, the clearest of the ancillary earthworks is a small amphitheatre, some 25m in diameter and unique in Britain. It comprises an oval area surrounded by quite high banks and has been interpreted as being used as an arena for weapons training. Today, the remains are confused by the road, a modern wall and a raised tramway from the Braich Ddu slate quarry which bisects the centre. There are slight but definite earthwork remains (possibly belonging to further practice camps, or part of a vicus) in the improved field outside the north-west bank of the first fort. Outside the south-east gate are the remains of the bath-house excavated in the 19th century, while on the other side of the road was a large courtyard building, probably a mansio or guesthouse. Beyond these are the remains of the bridge abutment. Between these buildings and the amphitheatre lie the ‘parade ground’ and a series of enigmatic earthworks (sometime interpreted as a ‘tribunal’ (saluting podium), but possibly simply the remains of quarry. The parade ground – a levelled space about 120m square – is a rare survival. The short military history of the fort may explain its unfinished state: the northern half, in contrast to the crisp southern section, is insufficiently levelled. The leat which supplied water to the bath-house runs between the ‘tribune’ and the parade ground. It can be followed for some way up the river. Two other leats carried water through this valley. The upper one, which can be traced for 200-300m to Llyn yr Oerfel, runs at he level of the principia and may have reached the fort on a raised launder. North of the quarry tramway are a number of natural hillocks: nearby, seven small square burial mounds, very low, can just be recognised on the nose of the westernmost rise, close to the later field bank. Like the cemetery on the east side, these graves were placed in accordance with Roman tradition, close to the road. The road, once over the bridge, heads south-east past an enclosed cemetery (300m away, just north of the road). The most notable monument is a fine, square, ditched barrow. This road (as well as the regularly placed scoops from which its material was quarried) has been traced by recent aerial photography to run over two miles to a series of eight military practice camps (in two groups) at Dolddinas (although there may be more), judged the best preserved in Britain. The situation here (a short distance from the main fort and close to a military road) is typical. About six miles south of the fort, at Pen y stryd, are the remains of two tile kilns, situated adjacent to the road to Brithdir (see above) and a source of water: suitable clay could be obtained from about 1m away. They may have supplied the fort with bricks and floor and roof tiles for the fort buildings. The Roman road itself is clearly visible here (especially from the air) as two parallel ditches with a slightly raised roadway or agree between them as it runs down the northern slope and approaches the stream.


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