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Tanat Valley Historic Landscape

Historic Landscape Characterisation

The Tanat Valley


Three groups of defensive earthworks of distinctly different dates fall within the Tanat Valley - later prehistoric hillforts, defended enclosures of Iron Age and Romano-British type, and medieval earthwork castles. The significance of these monuments within the landscape has been both functional and symbolic, and some are sufficiently prominently sited that they form major components of historic landscape character areas in their own right, taking their essential landscape setting into account.

Later prehistoric hillforts
Two major hillforts fall within the Tanat Valley - Craig Rhiwarth hillfort and Llwyn Bryn-dinas hillfort. Craig Rhiwarth hillfort, defended by a single stone rampart, on the large and imposing crag on the southern edge of the Berwyns overlooking Llangynog, towards the western end of the Tanat Valley. Little excavation has been undertaken within the hillfort and there is consequently little known about its history. The interior of the hillfort is unique within the region in containing a large number of circular stone structures which seem to represent late prehistoric houses. General comparison with Llwyn Bryn-dinas and other hillforts in the region suggest that the settlement may have begun life in the later Bronze Age period and possibly continuing into the Iron Age. It has been suggested that, possibly like the hillfort at Llanymynech, to the east of the Tanat Valley, that one of the functions of the hillfort may have been to control copper resources. Prehistoric mining is possibly represented by early opencuts on the southern side of the hill, just above Llangynog.

Llwyn Bryn-dinas hillfort is defended by a single stone rampart, enclosing an area of just over 3ha on the summit of a distinctive conical hill, at the point where the valley narrows, just to the east of Llangedwyn. Small-scale excavations at the hillfort have indicated that the hillfort was defended by an impressive stone-faced rampart constructed in the later Bronze Age, in the period between about 1100-800 BC. There is evidence that the hillfort was also occupied during the Iron Age, in the period between about 400-0 BC, at which time there is evidence of both iron and copper alloy technology being undertaken, the latter possibly using a distinctive type of copper ore which may have been mined at Llanymynech. The hillforts in the region appear to have ceased to be used as defended settlements following the Roman conquest in the later first century AD.

There is no certain evidence that either of the hillforts represent permanent settlements that were occupied for very extensive periods. They might both have been constructed or reoccupied for protection or to control resources in response to relatively short-term emergencies or contingency arrangements at particular times of unrest, and there is no certainty that the two were contemporary. It seems probable that they were constructed by distinctive tribal groupings under the authority of a military elite and that they represent only one element of the contemporary settlement pattern, parts of which are represented by the defended enclosures noted below.

Defended enclosures of Iron Age and Romano-British type
Five single or double ditched enclosures are known from the Tanat Valley which belong to types which are generally considered to be of later prehistoric or Romano-British date, although there is a possibility that some of the sites may be of either Neolithic to Bronze Age date or alternatively of early medieval date. Four of the enclosures are cropmark sites which have been identified by aerial photography and are no longer visible at ground level. It is probable that other sites of this type still remain to be discovered. All the sites lie on either the lower hills or on the valley bottom. One of the sites, Plas Uchaf, lies on a low hillock at the foot of Llwyn Bryn-dinas and in this instance traces of the banks thrown up from the enclosing ditches are still visible, giving the appearance of a small hillfort. Soil from the ditches of the cropmark enclosures most probably formed enclosing banks intended to provide some defence for buildings, property and stock retained within the enclosure. Excavations elsewhere within the region have shown that enclosures of this type are likely to represent farmsteads occupied by socially elite, extended family groups and associated with a mixed arable and pastoral economy.

Earthwork castles
Three certain and one possible mottes fall within the Tanat Valley - Tomen Cefn Glaniwrch, Tomen y Maerdy, Tomen Cefn-cch, and possibly Castellmoch, although little physical evidence survives of latter. The sites form part of the concentration of timber castles built in the Welsh borderland following the Norman Conquest, in the period between about AD 1100-1300. Little is known of the history of these sites in the Tanat Valley, but a little can be gleaned from their siting and form, and from place-name evidence.

The Tanat Valley fell beyond the extent of the marcher lordships until the 1280s and it is possible that all the mottes may have been built by native lords shortly before or following the partition of Mochnant in 1166. Two of the mottes fall within the commote of Mochnant Is Rhaeadr and two within Mochnant uwch-Rhaeadr. There are other suggestions of deliberate pairing. All the sites are reasonably equidistant from the boundary of the two commotes and in each case one of the sited on the valley bottom, next to the Tanat, the matching pairs lying on higher ground to the north between 1.5-1.8km the north. The patterning evident here is not commonly paralleled elsewhere, however, and it is therefore uncertain how much it is safe to read into it.

As noted above, there is little surviving evidence of the original form of Castell Moch. In the case of Tomen y Maerdy, the matching motte near the banks of the Tanat, some trace of an outer bailey is possible, though is not clearly visible today. By contrast, the large mottes at Tomen Cefn-cch and Tomen Cefn Glaniwrch both appear to be without accompanying baileys. Unlike Castell Moch and Tomen y Maerdy they are both prominently sited, with commanding views of the valley - so much so that Tomen Cefn-cch provides one of the most comprehensive views of the valley as a whole. To this extent, these two mottes have the appearance of outposts or watchtowers for the two lower-lying mottes. Each of the mottes would originally have been encircled by a broad ditch approach by means of a timber bridge, and would have been surmounted by a timber palisade, tower and/or other buildings capable of housing and protecting a small force in times of emergency. Being costly to build they would each no doubt have been symbolic representations of lordly power, wealth and authority of a kind still evident in the late 14th century, captured in Iolo Goch's description of Owain Glyndwr's residence at Sycharth, a matter of a few miles to the east.

Castell Moch and Tomen y Maerdy may have been the principal mottes within their respective commote each associated with a lord's llys (court) even before partitioning of Mochnant, and thus centres of civil administration and justice within each commote,, Castell Moch - for Castell Mochnant - possibly being the senior of the two and possibly the caput or seat of power of the undivided commote. Indeed, the name 'Maerdy' may show that the house (ty) of the lord's steward (maer) - one of the principal officers of the commote - lay at or near the site. There is no evidence that the marcher lordship of Chirk was ever administered by officers bearing the name of maer, which may either confirm that the motte was built before the 1280s or that the maer referred to was of lower office, that of maer of the lord's demesne.

Each of the mottes would have been sited within the lord's demesne or personal holding, but there is no clear evidence that any of the mottes represented a focus for nucleated settlement at any stage, and indeed this seems unlikely - Castell Moch being sited in poorly drained land on the brink of the Tanat and Tomen y Maerdy hidden from view at the foot of a narrow ravine, with no good farming land in the immediate vicinity, and the two subsidiary mottes being sited on high and possibly at that stage unenclosed land. The evidence that the mottes provide about settlements is therefore strictly limited. More specifically, there is no clear evidence that they were directly associated with native bond settlements (maerdrefi) which probably existed within each commote. Any administrative functions that the two mottes in Mochnant Is Rhaeadr Tomen (Cefn Glaniwrch and Tomen y Maerdy) might ever have had was undoubtedly transferred to Llanrhaeadr-ym-mochnant as this developed as a market town in the 13th century.

The importance of the two principal mottes had almost certainly waned by the later 13th century at the latest, at the time when Llanrhaeadr-ym-mochnant received its market charter and would have become the administrative centre of Mochnant Is Rhaeadr.

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