Summary Description and Reason for Designation
The following provides a general description of the Scheduled Ancient Monument.
The monument comprises the complex buried remains of two successive masonry castles of the Mortimer family occupying either end of the summit of an isolated and naturally defended ridge known as Castle Bank within a loop of the river Ithon. The hilltop is nearly 400m long and a maximum of 200m wide, and is surrounded on all sides except the north-east by steep slopes, which have been enhanced by scarping and ditching, possibly representing the remains of a later prehistoric hillfort. The earthwork remains of other structures occupy the enclosed space between the two castle sites, some of which may relate to a later llys or courthouse described in late medieval sources. Associated with the successive castles was a short-lived medieval borough, thought to have been located in the vicinity of the surviving parish church at the southern foot of the ridge.
The site was closely linked to the Mortimer family, one of the foremost baronial dynasties of the middle ages and dominant Marcher lords active in the in the conquest and governance of Mid Wales and its central borders between the 12th and 15th centuries. The first castle on the site is likely to be that founded by Ralph Mortimer in 1242, after he had consolidated his power in the Maelienydd area under a treaty made with Llywelyn ap Gruffudd following victory over the Welsh in 1241, replacing an earlier caput at Dineithon, under a mile to the west. In 1262-3, the resurgent Welsh under Llywelyn ap Gruffudd seized or destroyed Marcher castles holdings across Maelienydd and Elfael, including Cefnllys. Under the Treaty of Montgomery in 1267, Ralph’s son, Roger Mortimer was allowed to rebuild at Cefnllys in exchange for his loyalty to Llywelyn rather than Henry III. Work seems to have started soon afterwards, a complaint from Llywelyn to Edward I in 1272 concerning the scale of the new works suggesting that construction of the second castle (a ‘wide and deep ditch’ is mentioned) was well underway, rather than the agreed repairs to the earlier structure, while Mortimer had still not pledged the promised loyalty to Llywelyn.
The new castle appears to have been garrisoned but to have seen little action during the Welsh wars of 1277 and 1282, and remained in the hands of successive Mortimers, appearing in lists of their holdings throughout the later 13th and 14th centuries, reverting briefly to the Crown on a number of occasions such as the 1322 disposession of Roger Mortimer and his execution in 1330. Repairs to Cefnllys under the Crown are recorded in 1356, and the castle had again reverted to Crown control when the Glyndwr rebellion broke out in 1401. The castle was garrisoned during the uprising and may have been ‘burned and wasted by the Welsh rebels’ in 1405, although this has been disputed. Following the death without heir of Edmund Mortimer in 1425, Cefnllys passed to his nephew, Richard, duke of York, who took up his inheritance in 1432, although he may never have visited it.
During the 15th century, Welsh figures begin to appear in positions of managerial responsibility, and it is in this context that the poet Lewis Glyn Cothi addressed four poems of praise to the constable of Cefnllys and receiver of Maelienydd, Ieuan ap Phylip and his wife Angharad. The exact date of these is unclear; they probably belong in the period 1432-59, or, less likely, as late as 1463-83; Ieuan’s career is not otherwise recorded. The poems give an interesting if effusive description of a grand, presumably timber framed hall house on the site, which may be represented by the footings of a group of rectangular structure in the saddle between the two castles. Ownership of the site passed from Richard, duke of York to his son Edward, who was crowned Edward IV in 1461, thus delivering Cefnllys definitively into Crown hands. In 1493 the site is among a number of mainly ruinous castles granted to Prince Arthur, firstborn son of Henry VII, and it was described as ‘now downe’ by John Leland in the early 16th century. In 1687 it is mentioned as ‘the ruins of an old castle’.
The earlier castle is likely to have occupied an artificially elevated and ditched platform at the north-eastern end of the ridge. This is now much disturbed by later quarrying and associated spoil tips but traces of at least one rectangular structure may represent the buried lower levels of an internal keep and other buildings. Stony banks define possible small bailey enclosures to the south-west and north-east. The second castle was probably the smaller, almost square masonry ward at the south-western point of the ridge, isolated from the hilltop and the approach to the north-east by a massive rock-cut ditch, considered to be that referred to by Llywelyn in 1272 and comparable in scale to impressive ditching at the nearby 13th century Mortimer castles of New Radnor and Tinboeth. The enclosure contained a central round or octagonal tower, the walls of which are likely to survive to a height of several metres under the rubble. The footings of a possible gatehouse survive in the north-east corner. A further small enclosure to the south-west of this probably served as small bailey, while new defences along the edges of the hilltop to its north-east and across the saddle between the two summits may also belong to this phase. The grand late medieval hall-house referred to by Lewis Glyn Cothi probably stood in the saddle of the summit between the two castle sites, where traces of three substantial and apparently later rectangular structures are visible within a lightly embanked enclosure. It is unclear whether any of the earlier buildings were still in use by this time. Numerous other archaeological features are visible on the summit and slopes of the site, including embankments and enclosures, further possible building platforms, quarrying and traces of cultivation. These are difficult to date precisely, though many do appear to be later than the main occupation of the site.
The monument is of national importance for its potential to enhance our knowledge of medieval defensive and domestic architecture and practices and specifically the development of castle building in the central Marches and on the vast Mortimer estates. In spite of the limited upstanding masonry it retains significant archaeological potential, with a strong probability of the presence of both structural evidence and intact associated deposits relating to the different phases of the site. Cefnllys still forms a striking and prominent feature in the landscape of the middle Ithon valley, and shares group value with the possible predecessor motte at nearby Dineithon and the contemporary church, borough site, field systems and possible deer park occupying the valley bottom immediately to the south.
The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.