ABERYSTWYTH, also Lampadarn Vaur, also Aberrheiddiol.[924] In 1109 Henry I. deposed Cadwgan, a Welsh prince who had purchased from the king the government of Cardigan, and gave that country to Gilbert, son of Richard, Earl of Clare, who took possession, and built a castle "opposite to Llanbadarn, near the mouth of the river Ystwyth."[925] This was undoubtedly the precursor of the modern castle of Aberystwyth, but it is doubtful whether it was on the same site; the present ruins are not opposite Llanbadarn. The castle was as important for the defence of N. Cardigan as Cardigan Castle for the south. It was taken at least seven times by the Welsh, and burnt at least five times. The present ruins are not earlier than the time of Edward I., and there is no motte or keep. [H. W.] *BLAENPORTH, or Castell Gwythan (Fig. 41).--Also built by Gilbert de Clare, and evidently placed to defend the main road from Cardigan to Aberystwyth. The motte and bailey are still remarkably perfect, as shown by the 25-inch Ordnance Map. YSTRAD PEITHYLL.--Another of Gilbert de Clare's castles, as it was inhabited by his steward. It was burnt by the Welsh in 1115,[926] and is never mentioned again, but its motte and ditch still survive, with some signs of a bailey, close to the little stream of the Peithyll, near Aberystwyth. [H. W.] CHASTELL GWALTER, or Llanfihangel, in Pengwern (Fig. 41).--Castle of Walter de Bec, probably one of the barons of Gilbert de Clare. First mentioned in 1137, when it was burned by the Welsh.[927] There is a small but well-made motte and part of an adjoining bailey standing in a most commanding position on a high plateau. The ditch of the motte is excavated in the rock. [D. H. M.] [Illustration: FIG. 41.--MOTTE-CASTLES OF SOUTH WALES. Cilgerran. Blaenporth. Chastell Gwalter.] *DINERTH.--Also burnt in 1137; restored by Roger, Earl of Clare, in 1159, after which it underwent many vicissitudes.[928] Probably originally a castle of the Clares. "In the grounds of Mynachty, in the parish of Llanbadarn Tref Eglwys, is a small hill called Hero Castell, probably the site of the keep of Dinerth Castle."[929] The O.M. shows a small motte and bailey placed between two streams. *CAERWEDROS, or Castell Llwyndafydd, also burned by the Welsh in 1137,[930] after which it is not mentioned again. "A very large moated tumulus, with foundations of walls on the top."[931] Probably a Clare castle. *HUMPHREY'S CASTLE, now Castle Howel, from one of its Welsh conquerors. The original name shows that it was built by a Norman, and it was restored by Roger, Earl of Clare, in 1159.[932] A moated tumulus near the river Clettwr marks the site of Humphrey's Castle.[933]