Trêcastle - From 'A Topographical Dictionary of Wales' (1849)
TRÊCASTLE, an ancient ward of the borough of Brecknock, in the parish of Llywel, hundred of Devynock, union and county of Brecknock, South Wales, 11 miles (W. by N.) from Brecknock; containing 289 inhabitants. It derives its name from a castle, said to have formerly existed here; but by whom the fortress was erected, or at what time, cannot be clearly ascertained, neither are there at present any vestiges of it, except an artificial mound or tumulus on the northern side of the turnpike-road, which is supposed to have been its site. The origin of the place is involved in great obscurity, nor has it been satisfactorily shown by what means it became a part of the borough of Brecknock, from which it was separated, as regards municipal jurisdiction, on the recent abridgment of the limits of that town. It is conjectured that, having formed part of the lands of Idio Wyllt, son-in-law of Bleddyn ab Maenarch, Trêcastle fell, with the other territories belonging to the family, to Bernard Newmarch; and that, thus becoming connected with Brecknock, the head of that baron's possessions, it continued to form part of the great lordship of Brecknock, from which it was not divided even when, in the reign of Henry VIII., Brecknock first became shire ground. The present small village of Trêcastle seems to have formed the old town of Lluel, or Llywel, under which name it is frequently mentioned in the charter of Brecknock. It is situated on the northern bank of the river Usk, on the high road from Brecknock to Llandovery, and consists of a cluster of several houses, including a good inn and posting-house, from which it derives all the little importance it possesses. Fairs are held on January 17th, April 5th, May 21st, August 14th, November 13th, and December 14th.