Castell Gemaron, which is also known as Castell Cym Aran, was a motte-and-bailey fortification raised in the late eleventh century by the Mortimer family. During the intermittent Anglo-Welsh wars of the twelfth and thirteenth centuries, the castle was regularly attacked and frequently changed hands. It remained in use until the 1360s.



Castell Gemaron, which is also known as Castell Cwm Aran, was raised in the late eleventh century to control a fording point on the River Arran and dominate an overland route between Knighton and Llandrindod Wells. It was probably built by Ralph Mortimer, an Anglo-Norman Knight who was a retainer of Roger de Montgomerie, Earl of Shrewsbury. Under the patronage of the Earl, Ralph invaded Maeliennydd in 1093 and probably established Castell Gemaron soon after.


The castle took the form of an earth and timber motte-and-bailey fortification. It was situated on the western bank of the River Arran which provided the site with strong natural defences. The flat-topped motte, which would have been topped with a timber palisade, was built over a rocky outcrop which accounts for its sub rectangular shape. A quadrangular bailey, protected by a rampart and ditch, extended to the north. A counterscarp bank augmented the defences of both motte and bailey on the eastern side to compensate for the higher ground that overlooks the castle site.


The earliest surviving record of the castle dates from 1144 when it was recovered by Hugh Mortimer after having previously been captured and destroyed by the Welsh. Circa-1150 it was captured by Cadwallon ap Madog who held it until his death in 1179. Thereafter it was taken back into Anglo-Norman hands and was used as a regional outpost by the Sheriff of Hereford. However, it was seized by Cadwallon's sons in 1182 and remained in their hands until they were evicted in 1195 by Roger Mortimer. The castle was attacked again in 1215, this time by Llywelyn ab Iorwerth, who burnt it to the ground. The castle was rebuilt no later than 1240 and seemingly remained in use as an important manorial seat until at least 1360.





Allen, R (1976). English Castles. Batsford, London.



Higham, R and Barker, P (1992). Timber Castles. Batsford.


Morgan, G (2008). Castles in Wales: A Handbook. Talybont.



What's There?

Castell Gemaron is a well preserved example of a motte-and-bailey fortification. A farmhouse is located within the bailey meaning there is no public access. However, the earthworks can be seen from the adjacent road.

Castell Gemaron. The castle is a well preserved example of a motte-and-bailey fortification. The site is overlooked by higher ground to the south and west. The flat earth platform just beyond the motte may have been the site of siege apparatus during one of the many attacks on the castle.

Castell Cwn Aran. The castle is also known as Castell Cymaran (or Cym Aran).

River Arran. The castle is located directly adjacent to the River Arran which was once a major waterway.

Getting There

Castell Gemaron is found 1.5 miles to the west of Llanbister Road Railway station off an unnamed road. On-road parking is possible with care.

Car Parking Option


52.325256N 3.244325W

Castell Gemaron

No Postcode

52.324007N 3.244641W