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Clywedog Valley
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Historic Landscape Characterisation

The Clywedog Valley: Llanidloes
Llanidloes community, Powys
(HLCA 1196)


Modern Severn valley town with medieval origins, which rapidly expanded to become an important regional industrial and commercial centre between the later 18th and earlier 20th centuries due initially to the woollen industry, later sustained by other manufacturing industries, and by metal-mining in its hinterland and its strategic siting on trans-Wales routes on former drovers’ roads, turnpike roads, and railway network, and a modern trunk road.

The area fell within the manorial townships of Cilmachallt and Glynhafren Iscoed in the 19th-century Montgomeryshire tithe parish of Llanidloes.

Key historic landscape characteristics

Modern town of medieval origins occupying the floor of the Severn valley near its confluence with the Clywedog, at a height of about 160-170 metres above sea level, recently described by Richard Haslam as ‘one of the nicest towns in Wales’. The valley floor is covered with deep well-drained silty soils derived from river alluvium, gravelly in places, which have historically been best suited to dairying and stock rearing on permanent and short-term grassland and with some cereal production where flood risk is low. The town is strategically sited at the junction of historically important communications routes linking mid and west Wales, at a locally wider part of the Severn valley, near its confluence with the Clywedog and Dulas rivers and close to a fording point on the Severn. The earlier part of the town occupies a terrace on the east bank of the river which rises gently to the east.

The date of the earliest settlement is uncertain, but the presence of the church dedicated to St Idloes, a daughter church of the clas church at Llandinam, suggests an early medieval origin. The holy well known as Ffynnon Idloes which formerly existed in the Lower Green area (close to the present football ground), may also date from this period. It seems possible that the church may have been attached to or become associated with a manorial centre by the medieval period, possibly associated with a poorly documented motte-and-bailey castle in the Smithfield Street and Mount Street area, though it is possible that this was associated with the borough created by the lords of Powys in the second half of the 13th century. The town, first documented in 1263, became an administrative and commercial centre for the commote of Arwystli Uwchcoed, with a grid-like street layout characteristic of planted medieval towns. The plan has two principal axes with four roads, now named Long Bridge Street, Short Bridge Street, Great Oak Street and Smithfield Street, originally focused on the market cross, where the Old Market Hall is now sited. The right to hold weekly markets and twice-yearly fairs was granted to Owain de la Pole, prince of Powys, by King Edward I in 1280. A corn mill was in operation by the 1290s. During the final decades of the 13th century and the end of the first decade of the 14th century its population expanded rapidly in size but possibly remained fairly stable during the later Middle Ages. The town remained relatively small and its predominantly Welsh inhabitants not particularly prosperous, and though its markets and fairs were only of local importance they were surprisingly lucrative. The town is thought to have been provided with defences during the Middle Ages which may have comprised a wooden palisade ditch, and though the course of these is uncertain at least two former gateways are indicated by the name High Gate on the west and Severn Porte on the north. Two bridges across the Severn, possibly both of timber, are shown on Saxton’s map of 1578.

St Idloes’ Church, with some surviving 14th- and 15th-century fabric, appears to be the only surviving medieval building in the town. The church underwent considerable rebuilding in the middle of the 16th century when the hammerbeam roof was built and when part of the arcade from the nave of the Cistercian abbey at Cwmhir was moved there. Further substantial restoration work took place in the early 1880s. Some evidence survives of a post-medieval tradition of timber-framed construction survives within the town, some with later brick facades. Notable buildings including the Old Market Hall which it thought to date to about 1600, Perllandy on China Street, which dates to about 1630, as well as a number of fairly high-status buildings of 18th-century date such as the Trewythen Arms, but the Angel Inn, which is dated 1748, remains within a vernacular tradition.

The town underwent a period of rapid growth during the later 18th and 19th centuries which for a time placed it in terms of size amongst the top forty towns in Wales, borne of a prosperity based initially upon the expansion of the textile industry in the early 19th century though like the like other Montgomeryshire factory towns at Welshpool and Newtown it retained its essentially rural character. There are several small weaving factories in the town which exhibit an interesting typological diversity from small back-yard workshops to the later more substantial mills which harnessed water power provided by the river Severn. There is little evidence for a purely domestic industry, though Highgate Terrace on Penygreen is an important example, with an open weaving loft. Later larger mills include the Short Bridge Street Flannel Mill of 1834, the Llanidloes Flannel Mill, the Glan Clywedog Mill, the Phoenix Mill and the Cambrian Mill. The intense economic depression of the textile industry and the resulting poor working conditions, unemployment and poverty were seen as the root cause of the Chartist riots in the town in 1839, which despite the transportation and imprisonment of many of those that had played a leading role in the disturbances, fuelled an enduring radical political tradition within the town.

A further spur to the expansion of the town in the early 19th century was provided by the release of land resulting enclosure of the lowland commons known as Upper Green to the south of the town and Lower Green to the north of the town together with a strip of land running up to Dol-llys north of the Severn, which were subject to parliamentary enclosure. The town also benefited from its position as an important communications centre, acting as staging point on the turnpike road to Machynlleth and Aberystwyth, and also developed as a commercial centre by virtue of the numerous metal mines in the hinterland to the west and north as well as continuing to develop as a market town for sheep, cattle, agricultural produce and as a commercial centre for the surrounding area. The town was well-endowed with purpose-built inns and shops in the 19th century of which many survive with little alteration, providing a clear demonstration of the economic function of the town and a mark of its prosperity. Well-preserved shop fronts in particular make an important contribution to the architectural character of the town.

By at least the 18th century, if not much earlier, building had become relatively dense along the two main streets meeting at the market hall. During the course of the 19th century there was some development in the ‘back-lands’ as burgage plots, gardens and open land behind the medieval street frontages became infilled with ancillary buildings associated with street frontage properties and some minor additional streets which accommodated terraces of workers houses, as well as a considerable amount of rebuilding and refronting of earlier buildings. During the 19th century there was also some expansion of the built-up area beyond its original medieval limits with terraces extending along the approach roads to the town and suburban development to the south and east and across the river to the north of the Severn. Significant variations in the size of houses are evident during this period, those close to the centre of the town being typically three-storeyed and relatively substantial whilst further away, especially in the back streets, are predominantly, smaller two-storeyed terraces, many of which seem to have housed industrial workers. Foundry Terrace, built in about 1860 to house foundry workers, formed part of an important development including a possible manager’s houses within yards of the railway works in Foundry Lane.

Although the town is located at a river crossing and has two bridges over the Severn, the focus of development is along the lines of through routes, and houses generally turn their back to the river. The two river bridges were designed by Thomas Penson. The Long Bridge, to the north of the town is a substantial stone bridge with three arches which was widened in the 1930s. The bridge was originally built in 1826 as part of the improvements to the turnpike roads northwards to Trefeglwys and north-westwards to Machynlleth and replaced an earlier timber bridge about 60 yards downstream and more directly in line with Long Bridge Street. The Short Bridge, on the road leading westwards to Llangurig is a stone bridge with a single arch built in 1850 replacing an earlier stone bridge.

The outer suburbs fringing the town, particularly those with a more picturesque setting to the north and west, include a significant number of substantial houses or rural ‘villas’, built or extended by industrialists moving out of the town and rural landowners wishing to have property in close proximity to it. These 19th-century detached residences in the vicinity of the town, include Dol-llys Hall of 1803-13, Dolenog of 1837-39, Mount Severn, of 1826 (built for the town’s mayor), Maenol of 1832, and Summerfield Park built by the Thomas Jones, owner of Cambrian Mills and Spring Mills. As a result, there is an exceptionally good sequence of 19th-century domestic and commercial architecture in the town together with some important public buildings and institutions, including the gaol of 1838-39, the Police Station, and the Public Rooms of 1838 (later the Laura Ashley shop), which was built to include a flannel market as well as a court and concert room. The town became an important regional centre of nonconformism, with chapels of various different denominations and possesses an important series of nonconformist chapels, with building or rebuilding dates of 1862, 1872-4, 1876, 1878.

Architecturally, building in the town displays an interesting sequence of development in the use of materials during the course of the 18th and early 19th centuries, in which timber framing was displaced by stone, frequently rendered, and by brick which came into more widespread use during the 19th century. Polite architectural fashion in the early 19th century dictated the use of render, sometimes lined-out to imitate ashlar, but from about mid century onwards there was greater ‘honesty’ in the use of materials within the town, which fostered a growing interest in the decorative properties of brick and slate. Although there is a range of materials and detail, not least a notable variety in brick colour, stylistically there is considerable uniformity, with Georgian symmetry and detail still being used well into the 19th century. Nonetheless, Llanidloes can also boast some extravagant interpretations of the domestic gothic style, most notably at 7-11 Cambrian Place and Brynderwen and Woodlands Road, whose exuberance also suggests considerable confidence in the adoption of this style. The transition from vernacular to polite architectural traditions is potentially an interesting indicator of rising levels of prosperity and sophistication. Traditional forms of planning such as the lobby-entry plan typical of the region, still occur in the 18th century, but polite architectural forms became dominant in the 19th century. This transition is also marked in alterations to existing building stock such as the refronting of timber-framed buildings in brick, for example, or their more comprehensive remodelling as at 40-42 High Street, which began as a row of single storeyed timber-framed cottages.

Whilst there are some examples of vernacular or regionally planned houses within the town (Perllandy, the Angel Inn, 4-6 Shortbridge Street, The Royal Head Inn, Shortbridge Street), much of the architecture takes the form of urban town houses and especially of terraced rows, the latter giving evidence for an organised, relatively formal building process associated with 19th-century urban development: composition was achieved either by the repeat of identical units, by reflected pairs, or other attempts at symmetry. There were also some examples of back-to-back housing, as for example at Brynhafren on Penygreen Road, again attesting Llanidloes’s role as an industrial town. The unified frontages of some terraces, as in Long Bridge Street for example, conceal a much more complex building history revealed to the rear, suggesting that these terraces may have been the result of the amalgamation of previously more fragmented holdings. Although the terrace is dominant, there are some important examples of individual town houses, including the former Trewythen Arms Hotel, which was built as a private house in the late 18th century but later became an inn. Castle House, Shortbridge Street was another later 18th-century townhouse. Possibly like other houses in the town, it was divided into two properties in 1837, probably as a consequence of the growth of the town during the 19th-century and its changing economic and social structure.

Engineering industries developed and expanded during the course of the 19th and early 20th centuries following the collapse of the textile industry, notably based upon the former Llanidloes Iron Foundry which specialised in the production of agricultural and mining equipment, and the Railway Works which represented a substantial industrial development within the town. Other significant industries in the town during the later 19th and earlier 20th centuries included the former leather factory at Spring Mills tannery and leatherworks which took over the premises of a former woollen mill, flour mill, malthouses, and the former gas works on Victoria Avenue, using coal brought in by rail. Printing became a significant industry in the town during the later 19th and earlier 20th centuries when the town developed a reputation as an active literary centre. Various printing works, generally occupying small premises within the town, were involved in the production of journals and other works of a religious nature for a number of nonconformist denominations, particularly in the Welsh language, Welsh choral music, travel guides for the burgeoning tourist market in mid Wales, and local newspapers.

The Llanidloes and Newtown railway was completed in 1859 and although somewhat unusually it remained detached from the national rail network for a couple of years it eventually became connected in 1861 once the Welshpool to Newtown line was completed. In 1864 the Mid Wales Railway line south from Llanidloes to Rhayader and on to Builth Road and Three Cocks was also been opened, which subsequently amalgamated with the Cambrian Railway Company. An unusually large and imposing railway station, built as the headquarters of the Cambrian Railway Company, was built on the south-east of the town centre in 1864. The station survives but many other former railway buildings and structures have now gone, including a goods shed, engine shed and turntable.

Due to increasing competition with road traffic by the middle of the 20th century the Newtown to Llanidloes line was closed to passengers south of Moat Lane Junction near Caersws in 1963, but continued to carry some freight until 1967, having been kept open to transport materials used for the construction of the Clywedog reservoir west of Llanidloes, whose construction was completed in 1966. The Llanidloes bypass, to the east of the town, first mooted in the late 1960s due to traffic congestion, was opened in 1991, partly occupying a new cutting created on the line of the former railway, well below the level of the former railway station.

Many of the industries which supported the town declined during the 20th century. As a consequence of local government reorganisation in 1974 the town lost its borough status.


Historic Environment Record; Cadw Listed Building descriptions; modern Ordnance Survey 1:10,000, 1:25,000 mapping and 1st edn Ordnance Survey 1:2,500 mapping; Anthony 1995; Barton 1997; Beresford 1988; Carr 1992; Carter 1965; Davies 1861; Davies 1973; Davies 1985; Davies 2005; Evans 1812; Hamer 1872-76; Haslam 1979; Horsfall-Turner 1908; Howell 1875-83; Jenkins 1969; Jervoise 1936; Jones 1954; Jones 1984; Jones 1985; Lewis 1833; Miles and Suggett 2003; Morgan 1983; Morgan et al. 1991; Morris 1976-68; Morris 1993; O’Neil 1934; Owen 2003; Parliamentary Gazetteer 1843; Pennant 1783; Rees et al. 2007; Richards 1969; Robinson 2006; Silvester 1992; Soil Survey of England and Wales; Soulsby 1983; Smith 1975; Spurgeon 1966; Thomas 1955-56; Vaughan Owen 1969-70

For further information please contact the Clwyd-Powys Archaeological Trust at this address, or link to the Countryside Council for Wales' web site at

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