The main source of the Afon Rhondda Fawr is a spring, Ffynnon-y-Gwalciau, at about 544m OD. The main headwater Nant Carn Moesen then descends rapidly, joining the tributary of Nant Selsig, below Pen Pych. At this point (in particular at Treherbert and Penyrenglyn) the valley floor widens slightly, though generally the valley is less than a quarter of a mile wide. There is little flat land, in either the main or the tributary valleys, an exception being the well-developed shelf in the area between Ton Pentre and Gelli. Between Llwynypia and Tonypandy the river flows south, then changes direction, flowing south-southeast to Porth and its confluence with the Rhondda Fach. The floor of the main Valley descends from 200m at Blaenrhondda, near the head of the valley, to approximately 110m at Porth.

The Afon Rhondda Fach rises from an upland marsh at 489m OD between Mynydd Beili-glas and Mynydd Bwllfa and flows via Twyn Rhondda Fach and Castell Nos, past Maerdy and Ferndale, southeast to Pontygwaith. At Ynyshir the river turns south towards its confluence with the Afon Rhondda Fawr at Porth. The valley of the Rhondda Fach is even more deeply entrenched, than the Rhondda Fawr, and except for the area between Maerdy and Ferndale, is steep sided with little valley floor development, as a consequence most of the post-medieval settlement of the area, apart from that at Maerdy and Ferndale is located on the valley side.

The landscape of the area was altered during the Pleistocene period, approximately 18,000 years ago, by glaciation to create the landscape we know today. The principle glacial collecting point in South Wales was the Carmarthenshire Fans and the Brecon Beacons, the northern face of which was the source of numerous corrie glaciers. The Pennant escarpment and Craig-y-Llyn was the only barrier effectively to deflect the main Fans-Beacons ice-flow and created an icecap of its own. It was this force of ice, which modified the Rhondda Valleys, producing typical glacial features, such as the corries or glacial cymoedd visible today at Cwmsaerbren and Cwmparc.

While limited pollen analysis has been carried out on archaeological sites in the area, these have concentrated on the analysis of material associated with the Bronze Age, and later periods. As a result local evidence of the earlier environmental conditions and indeed during the immediate post-glacial period is limited. It is assumed that as climatic conditions gradually ameliorated following the last glaciation, dense native woodland gradually extended over the area. The effects of man on this woodland is fairly dramatic; with progressive felling implied at least from the Neolithic, supported by finds of axes of the period from throughout the area. Pollen analysis from the Bronze Age burial cairn on Crug-yr-Afan, near Cwmparc, indicates a contemporary environment of heathland, with an open tree cover dominated by oak. Evidence suggests that by the end of the Bronze Age, the upland areas of the Rhondda, like most of the uplands were covered by extensive blanket peat.

It is evident that, despite the effects of man, the area retained its extensively forested nature throughout the medieval and early post medieval, until at least the beginning of the nineteenth century; the Ordnance Survey maps of 1814 and Colby's map of 1833, demonstrate the luxuriously wooded nature of the Rhondda Valleys at the time, corroborated by the contemporary descriptions of English visitors to the area, from John Leland to Thomas Roscoe. Further indication of the wooded appearance of the landscape survives in its place-names; many Coed (wood) names, such as Coed Penpych, Coed Llwynypia, and Coed Ynys-hir, Coedcae (woodpark) names, such as Coedcae'r Arglwydd, Coedcae Rhondda and Coedcae Hafod, and Gelli (grove) names, Gelli Ystrad, Gellifaelog and Gellidawel are evident.

However with the opening up of the area to the coal industry, the wooded nature of the Rhondda landscape was altered; the valleys were denuded of their forests for pit props, leaving only the small remnants visible today, now substantially added to by recent Forestry Commission plantations.

The earliest and perhaps most visual features of the pre-industrial landscape throughout the area are funerary monuments located within the uplands dating to the Bronze Age (2300-800BC); these features are numerous and include individual, impressive sites such as Bachgen Carreg (SAM Gm 234), Carn Fach, Carn-y-Pigwn (SAM Gm 372), Carn-y-wiwer (SAM Gm 323), Carn-y-Bica, Bedd Eiddil, Garnwen, Carn Fawr, Carn Fach, the cairn and cist on Mynydd Penygraig, and Pebyll among others. An interesting example is that of Crug-yr-Afan (SAM Gm 233), at the head of Cwm Afan. This is an unusual type for the uplands being a ditched barrow, similar to the bell barrows of Wessex, which date from about 2000-1450 BC. Excavation in 1902 revealed a composite mound, the lower part, comprising a clayey soil, is surrounded by a flat ledge or berm, and ditch. Cut into the subsoil beneath the mound was a central cist, containing a cremation, and a bronze dagger, grooved along it edges, of a type familiar in Early Bronze Age Wessex. A smaller stone cairn, originally surrounded by a kerb or ring of upright slabs had been raised over the lower mound. Groups of cairns are also found in the Rhondda area, such as that on Mynydd Ton, the cairn field on Mynydd Gelli (SAM Gm 354), which includes larger ring and kerb cairns, while at Tarren Felen-uchaf a further cluster of funerary monuments include a robbed ring cairn and the cairn groups on Mynydd Maendy, one of which when excavated in 1901 produced a damaged bronze dagger, pottery, including sherds of a cinerary urn and flints. These features remain visible in the landscape and indeed as visible features, in an often-featureless landscape, continue as reference points for current administrative boundaries.

Perhaps the most interesting place of legendary note and undoubtedly of ecclesiastical importance within the Rhondda is Penrhys. It was the supposed site of a battle between prince Rhys ap Tewdwr and Iestyn ap Gwrgant in c. 1085-88, the name, Penrhys ap Tewdwr, derives according to tradition from the beheading of prince Rhys ap Tewdwr; while the nearby Bronze Age cemetery of Erw Beddau became associated in tradition with the battle. Another interesting tradition is associated with the area, which maintains that Edward II took refuge here in 1326, prior to his eventual capture.

The early-medieval ecclesiastical history of the area is as yet largely circumspect, and little direct evidence survives, beyond the names of the Celtic saints of the area, St. Tyfodwg and Gwynno, who probably established small monastic cells during the 6th century at the sites of the later medieval parochial centres, i.e. at Ystradyfodwg and Llanwynno. The area appears to have been under the influence of the mother church Llanilltud Fawr (Llantwit Major), later reorganised following the Norman conquest of the lowland portion of Penychan under the control of Llantrisant, falling within the diocese of Llandaff.

During the medieval period the monastic grange at Penrhys with its chapel, shrine, and hostelry, the property of the Cistercian Abbey of Llantarnam, was particularly known for the healing properties of its well, Ffynnon Fair. The Cistercians are known to have carried out large-scale sheep farming on their estates, and to have given up sheep farming from the early 14th century, dividing the manor into over 30 holdings and leasing their lands. The shrine was later dismantled at the time of the dissolution in the 16th century following the removal of the statue of the Virgin by Royal decree in 1538. It is said that the timbers were taken to construct the nearby farm of Ty'n-tyle (Davies 1975; Pride 1969; and Williams 1990). The ecclesiastical significance of the landscape is maintained to the present day by the area's continued use as a centre of pilgrimage by the region's Catholic community, a visual reminder of which is the monumental statue of the Virgin erected near the site of the chapel in 1953.

The medieval ecclesiastical centres of Ystradyfodwg and Llanwynno (outside the Rhondda Special Historic Landscape) survive, though that of Ystradyfodwg is now swamped by 19th century urban industrial settlement, while its church, the parish church of St. John the Baptist, has been rebuilt several times, last during the 20th century.

The overriding ecclesiastical features of the Rhondda landscape are undeniably non-conformist chapels and 19th century churches. The earliest foothold of non-conformity was Cymmer in the lower Rhondda, where in 1743 the Cymmer chapel or Ty-cwrdd was built. Other early chapels include the Ynysfach Baptist Meeting House (1786), later renamed Nebo, at Heolfach, Ebenezer Chapel (1830) and Dinas, the first Methodist Chapel in the Rhondda (Lewis 1959). The area contains many fine examples of 19th century ecclesiastical architecture. The subject of RCAHMW surveys, these chapels and churches are important elements in the urban industrial landscape, characteristic features not only of the Rhondda, but of most Welsh urban settlements and physical reminders of the area's spiritual and social past.

The earliest evidence of human settlement in the Rhondda area is represented by finds of material dating to the Mesolithic period (10000-4400BC) recovered over an extensive area. The material includes assemblages and individual finds of flint, including cores, blades, flakes, scrapers and microliths often associated with charcoal. The distribution appears to indicate considerable occupation of the higher ground particularly at the upper reaches of the Rhondda valleys. Possible Mesolithic settlement sites include, Cefn-glas, Cwm Saerbren, Fforch above Cwmparc, Gwyneb-yr-haul, Mynydd Beili-glas, Mynydd Blaenrhondda, Mynydd Ton, Mynydd Tyle-coch, Mynydd Ystradffernol, Nant Lluest, Nant-y-gwair and the area around Maerdy Reservoir where flint assemblages and stray finds have been recorded. Little systematic investigation has been carried out on settlement of the period, apart from the excavation at Craig-y-llyn (Lacaille in 1962). It is considered that this evidence of human activity represents temporary upland hunting camps, occupied by hunter-gatherer groups as part of a seasonal migration pattern between the coastal lowlands and the upland Blaenau.

Settlement of the Neolithic (4400-2300BC), is again largely represented by stylistically dated finds of flint tools including petit tranchet axeheads, and petit tranchet and leaf shaped arrowheads. These finds are similarly frequently associated with charcoal. Site distribution is similar to that noted for the Mesolithic, and includes finds from Mynydd y Gelli, Mynydd Ystradffernol, Tarren Pantyffin and the find of a petit tranchet axehead find from the slopes of Mynydd Ynysfelo. Flint processing is also recorded on Mynydd Ty-newydd, and above Cwm Parc, while also of considerable interest is the dated late Neolithic hut floor located at Cefn-glas.

There is significant evidence for activity in the Rhondda during the Bronze Age (2300-800BC); however this is predominantly related to upland funerary monuments. The whereabouts of settlement is largely based on stray finds of flint tools, the distribution being similar to earlier periods. Bronze Age finds include a bronze tanged spearhead with ribbed blade from Blaenrhondda, an arrowhead from Mynydd y Gelli and a hoard of bronzes from the quarry also on Mynydd Gelli. A more tangible indication of settlement is perhaps the burnt mound site on Mynydd Maendy (Arch Camb. 1902, p. 258), this site type, characteristic of the Bronze Age, is thought to be associated with cooking.

The effect of human activity on the natural vegetation of the area is clear from pollen analysis carried out in the locality; this is at its height at the end of the Bronze Age, and it is perhaps no surprise that the first major impact of human settlement on the physical environment of the area dates to this and the following period, the Iron Age.

A number of late prehistoric settlement sites are known in the area, perhaps the most interesting is the site of Hen Dre'r Mynydd (SAM Gm 101), Blaenrhondda, the largest undefended Iron Age/Romano-British (800BC-AD410) settlement in south-east Wales, and a site of national importance. The site is situated, like other examples of its kind, on high open moorland; its location suggests occupation on a seasonal basis, when animals were moved to the higher pastures during the summer. The remains cover an extensive area of gently southeast sloping ground and comprise a range of round houses and enclosures and stretches of walling, which form an interlinked village of amorphous plan. The site, when excavated in 1921, revealed little apart from a small amount of iron and evidence of leather. This might suggest material poverty, but might equally reflect the seasonal nature of the site's occupation. Settlement appears to be continuous with occupation spanning both the Iron Age and the Roman period, here represented by the remains of late Iron Age/Romano-British round houses at Hendre'r Gelli; excavation at the turn of the century recovered pottery of 2nd and 3rd century date from the site. Also of considerable significance is the fortified hill top settlement of Maendy Camp (SAM Gm 99), a rare example of an Iron Age 'hillfort' in the Glamorgan uplands. The site, excavated in 1901, comprises a small horseshoe-shaped central enclosure surrounded by widely-spaced low outer banks, while located between the inner and the outer ramparts is a Bronze Age cairn. Like many other examples, the fortified settlement of Maendy, with its hill-spur location, small central enclosure and widely spaced outer banks, appears to have been primarily pastoral. The layout of the site lends itself more easily with the function of stock raising and protection, than defence of a territory.

The extent of early medieval settlement in the area is unknown; however it is likely that some measure of continuity of native settlement carried over from the late prehistoric/Roman period. The only definite indication of early medieval occupation, beyond the system of cross-dykes (see above), comes from the place-name evidence, e.g. Dinas and Bodrhyngallt and the dedication of the area's churches to early Celtic Saints. For example, the historic landscape area contains the site of a church dedicated to the 6th century St Tyfodwg at Ton Pentre (the parish church of Ystradyfodwg), while that dedicated to St Gwynno, (Llanwynno) lies just beyond the eastern border. The area appears to have been under the sphere of influence of the great monastic site founded by St Illtud, Llanilltud Fawr (Llantwit Major). It is probably significant that Llanilltud Faerdre (Llantwit Vardre), another site connected to St Illtud, lies nearby to the south; the Faerdre element of the name suggests that the church was closely associated with a maerdref, a secular Royal administrative settlement. The area surrounding the church of Ystradyfodwg is characterised by a widening of the river terraces, offering flatter good quality agricultural land, which would be ideal for settlement. The existence of a settlement of early medieval date, if not earlier, at this site is also implied by the high density of both earlier settlement, e.g. the prehistoric settlements of Maendy Camp and Hendre'r Gelli, and later settlement, e.g. the medieval house platforms on Mynydd Gelli and Mynydd Ton, on the higher ground surrounding the area.

The industrialised and urbanised nature of the valley floor throughout the area of special historic landscape has resulted in the significant loss of earlier settlement features. The cartographic record and place-name evidence affords some indication of the location of medieval settlement along the valley floor, as on the higher ground, i.e. hendre and hafod place-names. The surviving settlement features of the period are exclusively known from the higher upland areas. The settlement features are predominantly platform houses, longhuts, typically in set out pairs; these upland dwellings or hafodau appear to have been occupied on a seasonal basis and were associated with pastoral agriculture, chiefly based on the rearing of cattle. The platform house sites are typically situated at the upper break of slope of the valley side along the periphery of the extensive upland pasture, the location frequently reflects the upper extent of the post-medieval enclosure and encroachment. Further study of the cartographic evidence may allow a correlation to be made between the distribution of known upland settlement with that of valley bottom settlement. A well-preserved example of medieval upland settlement is to be found at Carn-y-wiwer, comprising two groups of typically paired house platforms (SAM Gm 323). To the north and east of the platform houses is a group of c. 19 small cairns associated with evidence of ploughing; these may be contemporary, with the cairns representing clearance material from the adjacent fields. Other sites of the period include group of four house platforms on Craig Tir Llaethdy, the characteristic platform house sites of Craig Rhondda-fach, Cwm Cesig, Cwm Lan, Mynydd Ty'n-tyle, and at Nant-y-Gwiddon, Mynydd y Gelli, Twyn Disgwylfa, and longhut settlements in Cwm and Nant Saerbren. Hafodau, or seasonal upland agricultural dwellings are also known at Cwm-y-fforch, Mynydd Ynysfeio, at Garreg Lwyd, Blaenrhondda, at Blaenycwm, and also at Hafod Fach, Hafod Fawr, Hafod Ganol and Hafod Uchaf, while unspecified medieval settlement exists at Penrhiw Castell Llaeth. Related features, belonging to the medieval or immediate post-medieval period include enclosures or pounds associated with the management of stock, examples remain at Ffald Lluest and Tarren Saerbren.

Platform houses, such as those at Carn-y-wiwer, and the remains of hafodau throughout the area recall exploitation of the uplands, often on a seasonal basis, for cattle, and later sheep, farming during the medieval and post-medieval periods. During the early post-medieval period it is thought that the hendre-hafod system was gradually superseded through a change in pastoral practice. The main aspect is a transition away from the seasonal movement of kinship groups with the cattle to communally organised individual shepherds. It is considered that lluest sites belong to the latter system (Locock, 2000). The Welsh clan system with its particular customs, legal system, land tenure and inheritance survived longer in Penychan, than the areas further south, which had been subject to early Norman domination; the effect this had on the development of post-medieval agriculture and the agricultural holdings themselves is of interest. Most of the freehold farms within the Rhondda had been established by the sixteenth century; though the processes behind their development and the date at which this occurred are as yet not fully understood, and require further detailed study.

The surviving post-medieval farmsteads are generally downhill-sited and set on sheltered, gently sloping hill-side/spur locations. The farms are mostly 17th century in date, and predominantly of the longhouse regional type, such as Nant Dyrys-uchaf (now substantially altered) and Gelli farm (hearth-passage group: long-houses, RCAHMW). Many of the post-medieval farmsteads have been removed by the industrial and urban growth of the 19th/20th century, though a number survive to illustrate a number of variations on the longhouse regional type or ty-hir, the characteristic farmhouse type in the Rhondda during the 17th and 18th centuries, in which traditionally the farmer, his family, farm labourers and livestock all lived under one roof. These structures were usually arranged at right angles to the slope of the hillside, with a byre at the lower level, and living accommodation at the upper level often with a central hearth between and sharing a common entrance, usually via the byre.

The best surviving example of the longhouse or ty-hir in the Rhondda, is Ty'n-tyle; probably early 17th century, it is of two and a half storeys, retaining a central hearth and original doorway to raised passage between hall and cowhouse, though a new entrance with porch has been made directly into the hall. This farmhouse, set in an excavated hollow at right angles to the slope of the hillside, is typical of the design of longhouses: an entrance, to the side of the central chimney, is provided directly between the byre, at a lower level, and the living accommodation; the original external entrance being via the byre (three-unit longhouse with hall between narrow inner room and cowhouse; hearth-passage group: longhouses with raised passage, RCAHMW). A similar example is that of Blaenllechau, an early 17th century, altered in 1761, comprising a three-unit longhouse with hall, heated inner room and cowhouse with raised passage (hearth-passage group: with raised passage, RCAHMW). A variation of the longhouse type can be seen at Bodringallt (Bodrhyngallt), another 17th century building, characterised by a direct entry at the centre of the house and no central chimney (Direct-entry group: end-chimney house, RCAHMW). Also characterised by a direct entry at the centre of the house and no central chimney is Hafod Fach (direct-entry group: end-chimney house, RCAHMW). Another interesting variation of the longhouse theme is the farmstead of Troed-y-rhiw, with central and gable fireplaces with entrance to the side of the central chimney, though without the direct entrance between the byre and living quarters. This is a three-unit, two-half storey lobby-entry-house, of c.1700, later rebuilt (Lobby-entry group: internal-chimney houses, RCAHMW).

Other less-typical post-medieval house types include Ty-newydd Farm, a 17th century three-unit, chimney-backing-on-entry house with storeyed porch and hall between outer and inner rooms, both heated (hearth-passage group: houses with hall outer and inner rooms, or type B porch-entry house), with a sundial dated 1652. The farmsteads at Cefn-llechau-uchaf and Ty-draw are also exceptions, classified as belonging to the miscellaneous group (RCAHMW). Contemporary agricultural buildings include a 4-bay 18th century barn at Blaenllechau; and a 4-bay barn with extra bay forming a cart shed, and a cattle shed at Hafod Fawr.

Piecemeal remnants of the agricultural landscape survive in areas away from the valley bottom, primarily on the steeper slopes and the upland ridges, where later industrial incursion has been less intense. While the traditional agriculture of the Rhondda area was based on a system of mixed farming, it is the pastoral element, the rearing of livestock, which has always been predominant and the archaeological record reflects this; for example the Iron Age hillfort of Maendy Camp, is characterised as being a 'pastoral' type, its layout more suited to corralling cattle than the defence of an area. The late prehistoric/Romano-British upland settlements of Blaenrhondda and Hendre-Gelli are both associated with enclosures and are perhaps best interpreted as seasonally occupied settlements associated with the use of upland pasture during the summer months.

As outlined in the settlement section above, this seasonal use is continued into the medieval period; the remains of medieval platform houses, associated relict field systems (e.g. the settlement at Carn-y-wiwer), enclosures and hafodau, (e.g. at Garreg Lwyd, Blaenrhondda, and in Blaenycwm) attest to this continued use; while indications of the whereabouts of the main winter settlements, or hendre, of the valley bottom are preserved by the early cartographic evidence. The stock would have been predominantly cattle, but sheep are also evident during the medieval period, especially on the land of the former monastic grange of Mynachdy Penrhys, where the Cistercians carried out sheep farming until the early 14th century. Interestingly the division of the monastic holding of Penrhys, into leaseholds, which occurred at the time, is considered to have resulted in the construction of boundaries. It is unclear, however, whether these boundaries remain as features in the landscape. It may be significant that a more regular pattern of larger fields is seen in the area of the grange. Generally, however, the surviving enclosure of the Rhondda, is predominantly characterised by a patchwork of small and medium sized irregular fields, as depicted on the Tithe and 1st edition OS maps, with the steeper slopes, especially in the Rhondda Fach for the most part densely covered by woodland. Boundaries, marking the extent of late medieval and early post-medieval encroachment and enclosure on the slopes, are mainly of dry stone construction, though cloddiau and hedged banks are also evident.

Physical reminders of post-medieval agriculture include sheepfolds, sheep shelters, beast-houses and lluest sites. The latter were upland shelters probably used by individual shepherds on a seasonal basis; and indeed a tradition exists which supports this. Although cattle production continued during the post-medieval period, sheep farming became the mainstay of agriculture, in the Rhondda as elsewhere in the Blaenau region. The farmers of the region frequented the markets or fairs at Neath, Merthyr, Llantrisant, Ynysybwl and Llandaff, using Porthmyn or drovers, whenever it was necessary to convey stock to markets further a field; the main routes used by the drovers out of the Rhondda were to the north, via Blaenrhondda and Hirwaun Common to Hereford and to the south via Llantrisant.

Although predominantly pastoral, a limited, though sufficient, amount of arable production was maintained, chiefly oats, barley and wheat and also the traditional root crops. Corn was grown in the more fertile fields on the alluvial flats and meadows of the Rhondda Fawr at Penyrenglyn, Gelli and Llwynypia and in the lateral valleys of Cwmparc and Fforch. Within the Rhondda Fach the lowland meadowlands were restricted to the area of Ynys-hir; elsewhere the cereal production was carried out on valley side terraces, where the farms were generally located. Oats were frequently cultivated in the valleys, and the Glynrhondda area was frequently referred to colloquially as Gwlad y Gyrchen (the Land of the Oat) in tradition. John Leland, who visited the area during the 16th century, noted that it was '…meatly good for Barle and Otes but little Whete'. The high plateau itself was seldom cultivated, only during times of extreme hardship; as a result of shortages of cereals brought on by the long wars against France and the restrictions of the Corn Laws, rye and oats were both cultivated at altitudes of 275m, at Penrhys, and above Glynfach Farm, Porth.

Farming as practised in the Rhondda continued along traditional lines during first half of the 19th century; the old Welsh plough drawn by a pair of oxen remained in use, while car llusg (sleds) and traditional flails also continued to be used. The state of agriculture in the Rhondda improved only after 1850, with increasing industrial markets and the end of the agricultural depression. Likewise the Rhondda retained a predominantly rural character with its extensive mixed woodland and barren upland landscape until the mid-nineteenth century and the development of the coal industry. At the start of the 19th century the only exceptions to the rural scene were a few small mining villages, such as Hafod, Cymmer and Dinas in the Lower Rhondda and the even smaller mining settlements in the Clydach Valley and at Ynys-hir in the Rhondda Fach. Benjamin Heath Malkin (1769-1842), writing in 1803, remarked upon the absence of settlement of any consequence in the area beyond occasional groups of labourers' cottages as at Penyrenglyn, Ystrad and Pontygwaith.

Agriculture fostered a variety of crafts, trades and small-scale industries, characteristic of a self-contained and secluded rural community, these including blacksmiths, masons, sawyers, hoopers, woollen manufacturer, weaver, tailor, thatcher and shoemaker. During the first half of the 19th century water grind mills were used to process wheat, barley and oats; with mills located at Cwmsaerbren and Glyncoli in the upper Rhondda Fawr, Melin-yr-Om (the medieval mill associated with the monastic grange of Penrhys) in the mid Rhondda, while the lower Rhondda was served by mills at Pandy, Dinas and Ty'n-y-cymer. The shearing of sheep was carried out in a communal fashion, and while black wool was set aside for knitting stockings, the remainder was either spun into yarn on domestic spinning wheels or woven into cloth or flannel; the finished product then taken to the pandy or fulling mill, in this case to the woollen 'manufacturi' and pandy at Tonypandy, which had been established in 1738 by Harri David.

The forests of the area also played an important role in the local rural economy. The cartographic evidence, such as the OS maps of 1814, or Colby's map of 1833, reveals both main valleys were 'luxuriously wooded'; this fact was supported by descriptions of travellers to the area from Thomas Leland to Thomas Roscoe and attested to by place-name evidence, such as the numerous coed, coedcae and gelli names. Forestry in the area was flourishing during the early 19th century; Rhondda timber was supplied to the Royal Navy during the Napoleonic Wars. Other timber based industries included charcoal production, several platforms or aelwyd gols associated with charcoal burning survive in the area, e.g. at Blaenrhondda and Gelli, while bark was used by the tanning industry. Though the uplands have been extensively planted with conifers during the latter part of the 20th century, what remains today of the Rhondda's formerly extensive mixed-woodland today is a mere remnant, regenerated following the demise of the area's coal industry and once exploitation, primarily for pit-props, had ceased.

The Rhondda has little in the way of truly defensive or military landscapes; the earliest 'defended', structure surviving in the area being that of the Iron Age (800BC-AD100) fortified hill top settlement of Maendy Camp (SAM Gm 99) on Mynydd Maendy overlooking Cwm Parc. Maendy Camp is rare example of an Iron Age hillfort in the Glamorgan uplands; the site excavated in 1901, is characterised as being of a 'pastoral' type, its layout comprising a small horseshoe-shaped central enclosure enclosed by widely spaced low outer banks. The nature of the site is more in keeping with a function of corralling livestock, rather than defence of territory. An Iron Age or early medieval defensive encampment or settlement is also suggested by the place-name of Dinas, although none is known from either the area of the post-medieval farm or current settlement of the same name within the lower Rhondda. While located above Blaenllechau is the Roman marching camp of Twyn-y-Briddallt (SAM Gm 259), a temporary encampment dating to the 1st century. There are only two other defensive structures in the area, these are both medieval in date, specifically the remains of the motte at Ynysygrug, and the medieval castle site of Castell Nos (SAM Gm 408), Maerdy; the former probably associated with the earliest Norman incursions into the area has been largely destroyed by the construction of the Taff Vale Railway during the 19th century, while the latter site, probably a native Welsh stronghold of Maredudd ap Caradog ab Iestyn, the Welsh ruler of Meisgyn during the late 12th century, is better preserved and retains defences including a man-made escarpment and a ditch on the north and west sides.

Documentary sources refer to two medieval hunting parks within the Lordship of Glynrhondda, one of which, Parc Cwm Brychinog, lies within the Rhondda Special Historic Landscape. The designation of the area as a Park has been preserved in the names of the farms of Parc-uchaf and Parc-isaf and of the valley itself, Cwm Parc. Parc Cwm Brychinog was divided into the farms of Parc-uchaf and Parc-isaf, Cwmdare and Bwlch-y-Clawdd during the Tudor period. The separate nature of the park area and its boundaries are to an extent reinforced by its geographical situation and setting, being located within a side valley, delineated by steep glacial escarpments.

The natural aspect of the Rhondda's landscape has been remarked on elsewhere; the area's wild and then densely wooded landscape attracted the attention of early 19th century traveller's and compilers of topographical works, perhaps the most famous being Benjamin Heath Malkin (1769-1842). Writing in 1803, Malkin remarked upon the absence of settlement of any consequence in the area and was also impressed by the 'union of wildness and luxuriance' and of the lower Rhondda Fawr Valley he describes the 'contrast of the meadows, rich and verdant, with mountains the most wild and romantic surrounding them on every side, is in the highest degree picturesque.' While of the upper Rhondda Fawr, he describes a landscape, 'as untameably wild as anything that can be conceived'. The area made an impression on early nineteenth authors of major topographical works such as the Rev. T Rees and S Lewis, while in 1836 Thomas Roscoe in his Wanderings through South Wales described the area as 'a wild and mountainous region where nature seemed to reign in stern and unbroken silence'. Even as late as 1847, the traveller Charles Frederick Cliffe could describe the area as 'the gem of South Wales and hardly surpassed throughout the Alpine North'. Despite the effects of over one hundred and fifty years of coal mining, and more recent widespread Forestry Commission plantation, the magnificent wilderness of the upper valley sides and mountain tops remains; however the landscapes of the lower valley sides and bottom has been largely altered beyond all recognition.

The earliest communication networks known in the area are the ridge way routes, cefn-ffyrdd (e.g. Heol Adam), which run the length of the three south-east-aligned ridges of Cefn-gwyngul, Cefn-Rhondda and Mynydd Meyrick and east-west routes across the north of the area above Llyn Fawr and via Maendy over Bwlch-y-clawdd into the Garw Valley. It is considered likely that these routes have been in use since prehistoric times, and that the Roman Road between the forts at Neath and Penydarren follows the line of one of these. These routes appear to survive into the medieval period, with access along them controlled by a system of early medieval cross dykes (8th-9th century), i.e. Ffos Toncenglau (SAM Gm 118) another near Bedd Eiddil at Bryn-du (SAM Gm 285), at Bwlch-yr-Afan (SAM Gm 246) and at Bwlch-y-Clawdd (SAM Gm 500), all placed at strategic positions on what appear to have been contemporary administrative boundaries.

The network of minor roads, tracks and paths leading over the valley sides into the uplands dates from the pre-industrial period, and are depicted on both the 1st edition OS, the Tithe map and earlier maps. Many of communication routes appear to have evolved to link early medieval and later medieval sites, such as the early medieval ecclesiastical centres of Ystradyfodwg and Llanwynno; as well as civil administrative centres such as Bodrhyngallt and Maerdy. It is thought likely that this network had become more complex by the early post-medieval period to serve the many freehold agricultural holdings, which were being established at least from the late medieval period. Communication appears to have been a significant consideration in the location of the monastic grange of Mynachdy Penrhys with its hostelry; the medieval pilgrimage centre would have been located on one of many pilgrimage routes, here no doubt following the traditional ridge way route, while also having access to its territory and the neighbouring valleys. The early ridge-way routes were only superseded as the main arterial routes through the area during the post-medieval period by the valley-bottom parish road, along which the industrial urban settlements eventually evolved.

The route traditionally used by drovers, porthmyn, during the post-medieval period is known to have exited the area to the north, via Blaenrhondda, Garreg Lwyd and Mynydd Beili-glas in the cartographic record. Other routes were no doubt also in use and the subject would repay further study.

Many of the tourists and topographical writers who visited the Rhondda during the early 19th century complained about the poor state of the ridge-way routes and frequent record is made of the neglect of the duty of statutory road labour is alluded to by the Court Leet at Llantrisant and of the Overseers of the Highways; the latter reported in 1815 that the parish road in Ystradyfodwg was 'in a very ruinous state', while reports as late as 1845 confirm little had changed. Prior to 1860 a major obstacle to travel was the absence of good bridges; there were few bridges in the Rhondda, fords being the usual method of crossing the rivers of the area. During the first half of the 19th century the chief bridges of the area were the two bridges at Cymmer, Y Bont Fawr (of stone and rebuilt 1764, the repair of which, cost between £20 and £30 per annum) over the Afon Rhondda Fawr and Y Bont Fach (of wood) of the Afon Rhondda Fach and others at Pont Rhondda, Clydach, Ynyswen, Ystradyfodwg, and Pont-Rhyd-Tew in the Rhondda Fawr and in the Rhondda Fach, at Pontygwaith, a late 18th century hump-backed bridge, and at Pont Lluest-wen, an early 19th century single-arched bridge. Though minor changes were made to the parish road, the construction of the Dinas tramroad and then the Taff Vale Railway became the main means of transport for the emerging industrialised area of the lower Rhondda.

With the industrialisation of the upper Rhondda between 1860 and 1880, improvements to the road network gradually gathered pace; initiated by the Bute Trustees, who laid a road of 50ft width across their property, Bute Street, Treherbert and High Street, Treorchy, along the route of the parish road. Later improvements include the surfacing of the roads within the area after the 1890s with tarred clinker and granite during the early years of the twentieth century. Subsidence from underground workings also became a perennial problem, resulting in the bridge and road reconstruction. The Pentre landslide of 1916 resulted in a major road construction, when communications between the upper and lower Rhondda were nearly severed. Later during the 1920s realignments of two of the traditional routes out of the Rhondda Fawr, at Blaenrhondda (i.e. the present A4061), further upslope of the earlier track, and that via Cwmparc, the current A4061/A4107, into the neighbouring valleys of Cwm Afan and Cwm Ogwr.

The early tramroads of Dr Griffiths, connecting Hafod, via the Doctor's Canal to the Glamorgan Canal at Treforest in 1809, and that of Walter Coffin opened by the end of 1810, have been mentioned already. These tramroads opened up the coal producing area of the lower Rhondda to its markets, even though later conflicts of interests arose over monopolies of transportation within the area.

Undoubtedly the most significant transport development in the study area was the construction of the Taff Vale Railway (TVR) and later the Rhondda and Swansea Bay Railway (RSBR). The TVR, which had reached Eirw in 1841, had been extended throughout the entire length of the Rhondda Fawr by 1856. Penetration of the lower Rhondda had begun in 1845 at the request of local coal entrepreneurs, Insole, Gethin and Lewis Edwards, who were about to open collieries at Cymmer and Nythbran. While the Rhondda Fach Branch had reached Ynyshir by March 1849 and by May of the same year the Rhondda Fawr Branch was at Dinas, a delay then occurred in further extension until the steam coal seams of the upper Rhondda had been proven in 1853. Thereafter, in accordance with the Extensions Act of 1846, the TVR Co. extended the line to Ty-newydd, reaching Gelligaled by December 1855 and the Bute Merthyr Colliery, Treherbert in early August of the following year. An additional branch line was constructed to link up with the Cwmclydach Colliery's incline at Pwllyrhebog after 1858 and the line extended in the Rhondda Fach from Ynyshir to Blaenllechau, the following year, encouraged by the speculation that the collieries at Pontygwaith and Ferndale would be successful in locating the steam coal seams. The TVR, and the Bute West Dock, Cardiff, were instrumental in the Rhondda area's establishment as an important coal producing area. By 1862, the TVR had been extended to Treherbert in the Rhondda Fawr and Ferndale in the Rhondda Fach, with passenger services being initiated to Treherbert the following year and to Ferndale by 1876. A private line (owned by Mordecai Jones) was opened the following year between Ferndale and Maerdy.

The Ely Valley Railway between the South Wales Railway and the first coal Level at Pen-y-graig was incorporated on 13 July 1857, and completed in 1860. In 1877, this line was extended to the Cambrian Collieries in Clydach Vale. New railway networks, effectively breaking the TVR and Bute estate's monopoly on rail transport in the Rhondda appeared after 1880. First in the form of the Barry Railway and the Barry Docks, under the directorship of notable colliery owners and others, David Davies (the Ocean Colliery), Crawshaw Bailey (owner of extensive mineral properties), Lewis Davis (Ferndale), Archibald Hood (Llwyn-y-pia), John Cory (Gelli), James Insole (Cymmer), and Edmund Hanney (the National, Wattstown). The line, completed from Barry to Hafod in 1889, was key to the growth of Rhondda's coal industry from the 1880s, with coal and coke carried increasing from 720,347 and 9,171 tons respectively in December 1889 to 1,386,435 and 34,254 tons at its height in June 1892. While a scheme to link the Upper Rhondda Fawr with the Docks at Swansea never achieved the levels of success originally anticipated; this was the Rhondda and Swansea Bay Railway, incorporated August 1882, and constructed in stages, reaching the Upper Rhondda and Treherbert by means of the Rhondda Tunnel on 2 July 1890, and completed to Swansea in December 1894. Much of the area's rail network has been removed with the industrial decline of the area, with only the line between Treherbert and Porth surviving, however, the former routes generally survive as cuttings and embankments.

Often linked to the main rail network were numerous minor tramways and inclines associated with the various collieries and stone quarries of the area, these include the scheduled incline haulage system at Cefn Ynysfeio (SAM Gm508), which retains its drum house among other buildings, incline and tramway of the National Colliery, Wattstown, the tramway incline (with engine house) to Coedcae Colliery (2nd edition OS 1900), later the Lewis Merthyr Consolidated at Hafod and the later example above Ynyshir. These now disused features frequently remain as prominent elements of the landscape, visible reminders of the industrial transport networks, which played an essential role in the area's development.

The increased population of the Rhondda during the second half of the nineteenth century, led to the opening of the TVR for passenger services and the introduction of horse-omnibus services during the 1860s at a number of places. By the 1888 the first system of horse-drawn tramcars had been introduced to the lower Rhondda to cope with the increasing demand, but discontinued by 1902 due to problems with the state of the existing roads. In the same year the Rhondda and the Pontypridd Urban District Councils obtained powers to electrify the railroad between Pontypridd and Porth. The Rhondda Tramways Act outlined the establishment of new electric tramways from Porth to Treherbert and Ferndale. The Rhondda Tramways Co. Ltd. was formed in 1906 and the following year the Rhondda Tramways Electric Supply Co. Ltd incorporated to supply the electricity. The new service began in July 1908 running between Trehafod and Partridge Road in the Rhondda Fawr and Pontygwaith in the Rhondda Fach, by 1912 further extensions had been opened between Ferndale and Maerdy, Penygraig and Williamstown, and Treherbert and Ty-newydd. Although the Tramway system was abandoned in December 1933 in the Rhondda Fawr and by February the following year in the Rhondda Fach as a result of the increased popularity of bus services, its effect on settlement layout between Ferndale and Maerdy in the Rhondda Fach is particularly notable.

Prior to the emergence of the coal industry as the dominant industry, the Rhondda was relatively un-industrialised. Apart from small local stone quarries used for small-scale agricultural and domestic extraction, and typical rural industries such as timber, charcoal, fulling and milling mentioned above, the only other early industrial concern appears to have been a small ironworks at Pontygwaith, noted as an old furnace on the first edition OS map (1875 surveyed, 1884).

Some limited exploitation of the area's coal reserves was occurring from at least the 17th century, later small-scale extraction is evidenced by 18th and 19th century estate maps. Lewis notes that the development of the coal industry falls into two distinct phases; the sinking of the first steam-coal pit in 1855 at Cwmsaerbren (Treherbert) being the dividing line. The first period of industrial extraction, c. 1809 and 1855, was typified by the exploitation of bituminous seams of the lower Rhondda area by means of small levels and shallow pits, pioneered by a few individual speculators; the second, 1855-1924, saw the accelerated growth of the industry throughout the Rhondda valleys, following the proving of high quality steam coal and the construction of the supporting rail infrastructure. Also notable with the urban and industrial development is the rapid increase in the number of stone quarries, particularly visible on the 2nd and 3rd edition OS maps, which supplied the local construction industry with ever increasing quantities of the local Pennant Sandstone.

The opening of the Glamorganshire Canal from Merthyr Tydfil to Cardiff in 1798 was the first effective stimulus for the industrial penetration of the Rhondda; the linking of the Glamorganshire Canal at Trefforest to Hafod via Broadway by Dr. Richard Griffiths' tramroad by 1790 and the leasing of the mineral rights to Jeremiah Homfrey of part of Hafod Fawr farm were crucial factors in the opening up of the Rhondda.

While Jeremiah Homfrey worked the Hafod Level from 1809 until his bankruptcy in 1813, it is Walter Coffin (1785-1867), who is regarded as the first and foremost of the industrial pioneers of the Rhondda and it is he who established the reputation of the Rhondda as the source of finest quality bituminous coal in South Wales. Coffin was the first to open levels, with at least five are known, and by 1811 had connected his workings at Dinas, Gwaunadda, and Graig-ddu by tramroad to Griffiths' tramroad. His first pit, Dinas Lower Colliery, sunk in 1812 and the first in the Rhondda, resulted in the discovery of the Rhondda No. 3 seam. The coal from the seam, initially marketed as 'Dynas No. 3', was to become famous as 'Coffin's celebrated coal', with a reputation for coking and smithying purposes. The enterprise expanded with the opening of successive workings, the Dinas Middle Colliery (1832), Brithweunydd Level (1839) and Gellifaelog Colliery (1845), the linking of the Coffin tramroad with the Taff Vale Railway (TVR) at Eirw and increased overseas markets. By 1845 Dinas was the largest 'sea coal' colliery (i.e. not connected with ironworks) in the Glamorgan uplands with an annual production exceeding 50,000 tons.

During the 1840s a combination of factors such as the extension of the TVR into the lower Rhondda, improved mining techniques, the opening of the West Bute Dock in Cardiff and increasing demand, encouraged further development of the coal seams within the lower Rhondda. From 1844 George Insole and his son James Harvey Insole operated at Cymmer; initially driving the South Cymmer Level to the No. 2 Rhondda seam. In 1847 they sank the Cymmer Old Pit to the No. 3 seam, followed by the Upper Cymmer Colliery (Haine's Pit) and later in 1855 by the New Cymmer Colliery. Many other individual speculators opened small levels and pits in the surrounding area, at Glynfach, Bedw, Porth, Llwyncelyn and Nythbran. The boom year of 1845 witnessed the opening of the Gyfeillion Colliery of John Calvert, while others were opened in the Rhondda Fach and at Cwmclydach, such as the Ynyshir Coal Company of Messrs Shepherd and Evans, the Troedyrhiw pit of Leonard J Hadley & Co. and the Ty-newydd Colliery of James Thomas, who was responsible also for the expansion of Troedyrhiw, while William Perch & Co were operating in Cwmclydach around the middle of the century.

Before 1855 mining of the deeper steam coal seams, extensively exploited in the neighbouring Aberdare Valley, was generally thought to be untenable in the Rhondda. Following the TVR's offer of £500 to the first to sink a pit to a depth of 120 yards below the river bed in the upper Rhondda, the Bute estate was the first to explore the full potential of the area, sinking a trial pit on its Cwm Searbren property in 1851 on the advice of their mineral agent, WS Clarke. The steam coal of the upper four-feet seam was eventually reached at a depth of 125yrds and on December 21st, 1855 the first steam coal dispatched to Cardiff on the recently extended TVR; a significant milestone in the exploration of the Rhondda's coal resources. On the success of the Bute estate, David Davis, a colliery owner in Aberdare, began exploratory sinking at Blaenllechau, in the Rhondda Fach in 1857. After considerable difficulty the four-feet seam was reached in 1862, at the increased depth of 278 yards. The TVR was simultaneously extended as far as Blaenllechau.

The exploitation of this newly proven steam coal resource was initially slow, only three new undertakings, Bute Merthyr, Tyle-coch and Ynysfeio, being sunk in the Rhondda Fawr before 1864, while entrepreneurs tended to concentrate their efforts on winning the upper coals in particular at Pentre, Bodringallt, Llwynypia and Penygraig. Only after 1870 did exploitation of the steam coal of the area increase, with rapidly growing demand, principally from the steamship companies and the British Navy, but also industrial installations in France and from the railways of Europe and South America, and the decrease in supply from traditional sources such as the Aberdare Valley. Other factors during the 1870s and 80s included general improvements in rail and docking facilities (i.e. the extension of the TVR along the entire length of both main valleys by 1870, the construction of the Barry Railway and opening of the Barry Docks in 1889), and within the mines themselves the application of mechanical power and a greater use of explosives. A total of 24 new pits were opened in the Rhondda valleys between 1870 and 1884 with a combined annual output of almost three million tons, the total output of the Rhondda coalfield being five and a half million tons. While few new pits were sunk in the years between 1884 and 1913, the intensive working and extension of existing concerns had increased coal production to its maximum level of 9,610,705 tons by 1913.

The largest of the mining concerns in the Rhondda during the period were: the Glamorgan Coal Company, Llwynypia founded by Archibald Hood; the Ocean Coal Company with pits at Ton Pentre and Cwmparc founded by David Davies; the Fernhill collieries at Treherbert and Blaenrhondda, founded by Thomas Joseph and Ebenezer Lewis; the Cambrian Colliery Company, Clydach Vale opened by Samuel Tomas; the Naval Colliery Company at Penygraig and Tonypandy; and Cory Brothers and Company at Pentre and Gelli in the Rhondda Fawr. The main concern in the Rhondda Fach was that of David Davis and Sons Ltd, who had 9 pits, by the last decade of the century these were joined by Maerdy (Mardy) collieries, founded by Mordecai Jones, the Ynyshir collieries of James Thomas and the National at Wattstown. While in the lower Rhondda Insoles Ltd had extended the Cymmer concern, sinking to the steam coal seams and with a new undertaking at Hafod, known later as Lewis Merthyr Collieries, opened by William Thomas Lewis (later Lord Merthyr).

Despite a slight fall in output during the early years of the First World War, recovering with the imposition of government control in 1917, production continued at the high level of eight and a half million tons to meet the demands of the Royal Navy, the first decline coming in 1921. The depth of the problem was at first concealed by a prolonged dispute in the US Coal industry and the French occupation of the Ruhr, to the extent that almost 40,000 miners were in employment and the population of the Rhondda reached an all time high of c. 169,000.

By the end of 1924 the coal industry was in depression brought about by factors such as loss of markets due to the Versailles reparations policy, the restoration of the gold standard, the development of hydroelectric power and above all the replacing of coal by oil as the main marine fuel. This depression was only relieved by the outbreak of World War II, and despite the high hopes generated with nationalisation in 1947, the coalmining bonanza of the Rhondda had effectively ended in 1924. During the latter half of the twentieth century the industry was plagued by geological problems, and many pits closed during the 1930s and 40s, and during the rationalisation, which followed nationalisation. Industrial unrest was also a common occurrence during the period, which culminated in the miners' strike of 1984.

The last remaining working pit in the Rhondda, Mardy Colliery, was finally closed on 21 December 1990, and in March 1996 the site was cleared to make way for an industrial unit. Today the most complete surviving example of a colliery in the Rhondda is the Lewis Merthyr Colliery, now the Rhondda Heritage Park Museum at Trehafod, near Porth.

The industrial and urban growth of the Rhondda is, in many respects, unique, and given the speed at which it developed and declined perhaps unequalled elsewhere. This dramatic growth is most apparent in the population figures for the parish of Ystradyfodwg. From a relatively static population of less than 500 before the first census of 1801, the population had doubled to 951 by 1851, trebling in each of the next three decades, reaching over 50,000 by 1891 and peaking at 167,000 in 1923-4.

Industrial settlement in the Rhondda area began on a small scale at the end of the 18th century and was initially confined to the lower Rhondda; the first upsurge of early industrial settlement coincides with the activities of Walter Coffin from 1812 centred on Dinas. During the 1840s settlement of the area gathered pace as Coffin, who owned 46 houses in Dinas by 1841, was joined by other entrepreneurs, including DW James at Porth, Leonard Hadley at Treodyrhiw and Messrs Shepherd and Evans at Ynyshir. While much of the initial housing comprised temporary wooden huts built for the sinkers of the pits, more permanent structures were also constructed; these were typically small houses, similar to the cottages of the rural peasantry. In time the two-storey single-fronted house built of the local Pennant Sandstone, such as those erected by George Insole the colliery proprietor at Cymmer and America Fach, Porth, became the most common type of house in the Rhondda, though isolated terraces of single-storey cottages, such as Glanselsig Terrace, Blaenycwm were also built. Larger terraces of 'mass' housing associated with colliery development are also noted for the period. Early development was limited, however, and primarily comprised the villages of Cymmer, Dinas, Eirw, Graig-ddu and Store House in the lower Rhondda, characterised by an informal, haphazard layout and set still within a largely rural context.

The expansion of settlement beyond the confines of the lower Rhondda area rapidly follows the exploitation of the coal reserves of the Rhondda Fawr and later the Rhondda Fach, which occurs during the 1850s and 1860s onwards. A rationalisation of house design also occurs during the 1860s, with dwellings generally increasing in size. Good examples from the period include the two-storey, single-fronted terraced houses Ton Row, Pentre and the two-storey, double-fronted houses of the Scotch Terraces at Llwyn-y-pia. The only in-depth study to date of housing in the Rhondda is that of MJ Fisk (Fisk 1995). Fisk charts the development of housing in its industrial and social context, from the early 'tai bac a ffrynt' and small square plan cottages, which would have been familiar to Walter Coffin in the 1840s, via the emergence of industrial housing during the 1860s, e.g. the Scotch Terraces, Llwynypia, to the housing reforms of the early 20th century and the emergence of welfare and council housing. The introduction of social legislation during the 1870s, notably the public Health act of 1875, and the establishment of the Ystradyfodwg Urban Sanitary Authority in 1877 with its adopted bye-laws (effective from 1879), had a significant effect on the later development and character of the urban landscape of the Rhondda. While these changes came too late for much of the housing in the Rhondda, the effect was to impose a strong uniformity of character, regardless of tenure or agency, on later urban development in the Rhondda.

The established housing styles include 2-storeyed terraced properties, both single and double fronted and the less frequent single-storeyed properties; the introduction of brick-detailing and the later use of brick and even concrete in house construction itself is also of note. The building styles, while not necessarily providing the only basis on which one character area is distinguished from another, each contribute to the general character of the urban landscape.

The characterisation of the industrial urban settlements has to a large extent relied on two pioneering geographical studies of the 1960s. These are Wayne KD Davies' morphological and functional study of central places applied to the settlements of the Rhondda (Davies 1968), and PN Jones' study of the form, structure and disposition of colliery settlement in south Wales (Jones 1969).

In short Davies' study is concerned with establishing the inter-relationships between morphology (i.e. form and structure) and function (i.e. intended purpose); he relates morphological studies to the dynamic processes, which created the urban morphological features, while examining the processes responsible for spatial variation in urban morphology in terms of their inter-relationships with function.

Davies notes that morphology originates from function, i.e. that the form of a building or set of buildings is based on the purpose intended, and that form as well as function, are subject to change over time. A time lag in the relation between the two is frequently observed, with form often changing less rapidly than function. For example building forms originally intended for domestic use (typically the ubiquitous terraced house) when taking on a secondary commercial function, apart from some minor adaptation remain, at least initially, largely unchanged with original and yet redundant features surviving. More elaborate shop fronts or rebuilding occur generally at later stages, and are dependant on the success of the venture(s) and the commercial centre itself.

Davies considers commercial cores to be collections of buildings, which are distinguished by homogeneity of function and usually compensated by heterogeneity of building styles, correlated with formal disharmony. This is the result of alterations to, and even replacement of the buildings to suit commercial functions, ultimately leading to a variety of building forms and styles, which reflect the period(s) when alteration to the building stock occurred.

Morphological analysis of commercial centres, requires certain factors to be taken into account: particular functions might produce specific forms or multifunctional forms, and that, form is dependant on function, not only for type, but also in degree of intensity, while the whole is set against the background provided by the architectural styles of the period. As noted above, a time lag is often experienced, with functions frequently operating within older forms, so that relict features remain recognisable. Conversely secondary conversion of structures can be reversed so that pre-existing forms are recovered.

Davies identified centres and attributed to each a functional grade based on intensity of land/commercial use. In addition he uses a morphological scoring system taking the ubiquitous Pennant Terrace form as the basic norm and allocating graded scores to four basic characterising categories, as follows:

The results of this analysis produced functional and morphological indices, and without going into the complexities of his findings, Davies' analysis allowed a correlation to be made between function and morphology. Davies identified that the morphological character of an area can be quantified and that it is dependant on the functional complexity of that area, and its development over time. Davies identified five functional grades of centres: A, B, C, D, and E, of which only types B-E are to be found within the area. This morphological/functional hierarchy has been useful as a basic tool in identifying general urban characteristics (Davies 1968).

Group B of Davies' functional grade of centres is characterised by having a distinctive central area comprising a core of larger commercial buildings, usually with modern shop fronts, to either side of which are lesser commercial premises of two storeys and modern shop fronts. These in turn give way to a mixture of commercial properties generally the result of house conversion and ultimately to unaltered residential areas. Within this category are the main commercial centres of Porth, Tonypandy, and Treorchy.

Group C is characterised primarily on the basis of house conversion, though distinctive commercial premises of two storeys and modern shop fronts are in evidence. Within settlements of this type a commercial function has evolved largely through conversion of the residential two-storey terraces by addition of wooden shop fronts and also the addition of a hard core of more distinctive commercial premises of two storeys and modern shop fronts, leading to a mixed urban landscape. Typical settlements of this group include Ferndale, Penygraig and Treherbert.

Group D of Davies' functional grade of centres is characterised on the basis of conversion, with a few modern shop fronts and distinctive commercial premises. The conversion of houses by wooden shop fronts typical of the very late 19th or early 20th centuries is prevalent. Typical of this group of settlements are Cwmparc, Gelli, Maerdy, Pentre, Pontygwaith, Ton Pentre, Tylorstown, Ty-newydd, Williamstown, Ynyshir and Ystrad.

Group E, the lowest of Davies' functional/morphological hierarchy of centres, comprises those settlements which failed to develop commercial centres and which have remained essentially residential in character, typical examples of this group include Blaenllechau, Blaenrhondda, Blaenycwm, Hafod, Llwynypia, Trealaw, Wattstown and Stanleytown.

Jones on the other hand looks specifically at the development of colliery settlement based on form and genesis, rather than the function/morphological hierarchy of commercial urban centres as in general; the manner in which a settlement develops has particular bearing on its historical character. The study provides a model and classification system, based on an analysis of settlement development throughout the South Wales Coalfield. He also notes, however, that his model in its simplest form is not fully applicable to the Rhondda Fawr due to the almost complete nature of the colliery settlement rapidly established in the area by 1878. To facilitate his analysis, Jones recognises three main phases or stages of Coalfield settlement development: first-phase (up to c. 1878); second-phase (c. 1878-1905); and third-phase (1905-1921). These phases have been adopted for the purposes of the present study.

The categories of settlement outlined within the classification system relevant to the study area, as presented by Jones, are as follows:

A. Composite Colliery Settlement, further sub-divided as: Aa, a nucleus of early, 1st phase (up to c. 1878) development, often including colliery company housing, normally containing the present commercial centre, examples being Cwm Clydach, Cwmparc Cymmer, Ferndale, Hafod, Llwynypia, Pentre, Penygraig, Porth, Tonypandy, Treherbert, Treorchy, Ty-newydd, Ystrad; Ab, large compact regular blocks of settlement, (largely) constructed during 2nd and 3rd phases, sometimes with evidence of estate control, e.g. Gelli, Ton Pentre, Trealaw, Tylorstown and Williamstown.

B. Second-phase (c. 1878-1905) Pithead Settlement: smaller than A, but frequently with a population of over 5,000 at the height of mining activity. These settlements were always initially orientated to one specific, or well defined groups of collieries, e.g. Maerdy and Wattstown.

C. First-phase (up to c. 1878) Pithead or Slant Settlement, which originate during the 1st phase pioneer colonisation of the valley unit and are invariably orientated on pits or slants. All remain small, and slant settlements in particular are often in isolated locations. Four sub-types have been recognised: C1, larger settlements orientated on 1st phase pitheads, which have remained relatively static; rare subtype as most focus of further expansion, e.g. Blaenllechau and Blaenrhondda; C2, small isolated terraces or cottage groupings, often of row type, which form fragments of colliery settlement, e.g. Abergorki; and C3, as C2 but with rejuvenation of house construction during the third phase (1905-1921), e.g. Blaenycwm.

The most characteristic feature of settlement in the Rhondda Fawr during the 1st phase (i.e. up to c. 1878) was the ribbon of settlement along the winding parish road. Mining colonisation had reached a relatively advanced stage, and even tributary valleys, such as the Clydach had been opened up. Specific pithead settlements were relatively rare in the area, Llwynypia being the best example. Generally the ribbon of settlement had expanded most where collieries had concentrated to any degree, such as at Treorchy or Pentre. During the first phase considerable breaks in settlement remained, such as between Treherbert and Treorchy, and between Ystrad and Llwynypia. The larger settlement units tended to follow grid-plan layouts and most colliery settlement in the Rhondda Fawr had developed in a more organic fashion, fostered by the widespread distribution of collieries and related to the main communication route of the valley, the parish road. Outside the main valley, however, both settlement fragments of isolated rows, such as Blaenycwm, Blaenrhondda, Blaenllechau, and in Cwm Clydach and large pithead units linked to adjacent collieries, such as at Cwmparc and Ferndale do occur during the period.

Though less characteristic, it is the pithead settlements, such as Maerdy, Tylorstown, and Wattstown in the Rhondda Fach, which are perhaps the most striking settlement features of the 2nd phase. These generally large pithead units were associated closely with the colliery or collieries they were constructed to serve. Within the Rhondda Fawr employment expansion during both the 2nd and 3rd phases (i.e. post-1878) related to the rapid expansion of settlement was almost entirely centred on existing collieries; and the distinctive settlement distribution was maintained as a result. This is typified by in filling in existing major concentrations and substantial additional ribbon development along the parish road. Another major settlement characteristic, fundamental to the development of the overall settlement pattern during both the 2nd and 3rd phases, was the growth of large adjunctive settlement units, notably at Clydach Vale, Gelli, Ton Pentre and Tonypandy. Jones notes that the development of settlement pattern based on the kernel-like growth of select nuclei and further ribbon development emphasized 'the maturity of the total pattern'.

Though some isolated settlement units, such as Blaenrhondda, Blaenycwm and Cwmparc, did experience growth during the third-phase, settlement expansion was generally on a more limited scale throughout the area than during previous phases. This, in spite of the increased potential for settlement flexibility created with the opening of new collieries in the upper reaches of both the Rhondda Fawr and the Rhondda Fach, e.g. Mardy, Ty-draw and Glenrhondda, (only Lady Margaret Pit ceased production). Another important factor, encouraging settlement expansion during the period, was improvement to passenger rail transport and in particular the construction of an electric tramway system, which operated in the lower Rhondda from 1905, and eventually served the entire area. The tramway system was largely responsible for the distinctive ribbon development between Maerdy and Ferndale along its route.

The agencies of housing provision in the South Wales Coalfield comprised the colliery companies, speculative property investors, and building-clubs of colliery workers, and to a lesser extent, owner-occupiers, the land-owning estates, and later local authorities. Of these, speculative property investors and building-clubs of colliery workers were predominant in the Rhondda, especially during the 2nd and 3rd phases. Housing built for owner-occupiers is less common and that for the land-owning estates rare indeed; Treherbert, where the Bute Estate built between 50 and 60 houses during the 1850s, being the only example of the latter in the Rhondda.

It is the role of the colliery companies that is perhaps the most interesting. Colliery companies were fairly major agencies of house provision during the initial pioneering phase, i.e. up to 1878, while during the 2nd and 3rd phases having a standard role in initiating housing construction, which was then invariably quickly followed up by other agencies of housing construction (i.e. building clubs, owner occupiers and speculative investors). Prime examples of the pioneering role played by colliery companies in the urban development of the Rhondda include the Scotch Terraces at Llwyn-y-pia, associated with Archibald Hood of the Glamorgan Colliery and David Davies and the Ocean Colliery's housing in Ton Pentre; both dating to the 1860s. Later examples of colliery involvement in the provision of housing are illustrated by the schemes implemented by H Taylor and Company at Tylorstown and the National Company at Wattstown in the Rhondda Fach. It is interesting to note that Lewis Merthyr Consolidated Collieries Ltd was the largest provider of company housing in the Rhondda valleys, accounting for 214 houses, that is 36.7% of company housing in the Rhondda Urban District during the post-register period, despite the focus of its mining activity being at Hafod in one of the most densely populated and most continuous area of settlement in the Rhondda (Jones 1969; Fisk 1995).

There are no obvious differences between the style of houses constructed for the various agencies, apart from a few of the more formally planned examples in Treherbert, built for the Bute Estate, e.g. St Mary's Alms Houses and the north end of Dumfries Street, both of which are symmetrical in plan with projecting central block and wings, and those constructed for local authorities after the third phase, e.g. council estates at Penygraig, Treherbert and elsewhere. The characteristic industrial housing of the area are variants on the ubiquitous linear two-story terrace of Pennant Sandstone, though during the 3rd phase semi-detached properties become a little more frequent where space allows, e.g. at Blaenycwm. Where differences in house styles are noted these are usually due to period or, later, the social aspirations of the intended occupants.

Perhaps the most significant recent impact on the urban landscape is the closure, demolition and reclamation of the area's industrial sites, predominantly collieries, upon which the settlements were originally based and dependant, apart from that at Trehafod, currently the Rhondda Heritage centre. Other recent impacts include the provision of modern highways and bypasses, and the construction of industrial estates, factories, schools and housing estates, frequently on land between the original communities, made available by the clearance of the former collieries and their associated transport networks. These have all to an extent modified the historic character of the urban landscape, though enough remains to distinguish the various settlement areas and allow an understanding their development.