YSTRAD-OWEN, or YSTRAD-OWAIN, a parish, in the union of BRIDGEND-AND-COWBRIDGE, hundred of COWBRIDGE, county of GLAMORGAN, SOUTH WALES, 3 miles (N.E.) from Cowbridge; containing 196 inhabitants. Ithel, surnamed Dii, or " the Black," Prince of Glamorgan in the tenth century, occasionally resided here; and the place is distinguished in the historical annals of the principality as the scene of a desperate battle between the invading Saxons and the ancient Britons under Conan ab Seisyllt, in the year 1031, when that chieftain and all his sons were slain. It derives its name from Owain ab Collwyn, who lived here in a palace, of which the site is marked by a large tumulus near the church, now covered with a thriving plantation. The parish comprises a moderate extent of good arable and grazing land, and a portion of common, affording pasturage for sheep and young cattle: the surround-- ing scenery is pleasingly diversified, and enlivened with some interesting features. Ash Hall is a handsome modernized mansion, situated on an eminence above the church, commanding a fine view of the whole Vale of Glamorgan, from the house to the sea, with the town of Cowbridge in the foreground, and the high lands of Somersetshire in the distance. . The living is a perpetual curacy, endowed with £1200 royal bounty, and £200 parliamentary grant; net income, £41; patrons and appropriators, Chapter of Llandaf. The church, dedicated to St. Owain, is a very small ancient edifice, not remarkable for any architectural details. On a tablet is an inscription recording that Sir Lionel Jenkins, Knt., presented to each of the churches of Ystrad-Owen and Llanblethian a tenor bell; and that Evan, his brother, gave a house and thirteen acres of land, yielding £22. 4. per annum, to repair the bells, directing the surplus to be appropriated in apprenticing children, and relieving aged labourers not able to work, in both parishes, in equal shares. Sir Lionel also bequeathed a fund for clothing the last description of persons, which amounts to £20 every fourth year for this place. On a hill to the south of the church are some inconsiderable remains of the ancient castle of Till-yVaen, or Tilavan, one of the twelve fortresses erected by the followers of Fitz-Hamon, by whom this portion of the conquered territory was granted to Sir Richard de Seward, in whose family it continued for many generations; it formed part of the dowry of the widow of Hugh le Despencer, when affianced to Guy.de Brien, and was subsequently conveyed by marriage to the Dukes of Lancaster, and is still included within the duchy. In a field near the village were two large monumental stones, rudely ornamented, which were supposed to have been placed at the head of the graves of Owain ab Ithel and his consort, and thence called the King and Queen stones; but they have been removed for some time. Near the churchyard, in a field adjoining it on the west, is a very large tumulus, of which not even any traditionary account has been preserved. An annual assembly of the bards was held here for many years, under the auspices of the ancient family of -Hensel, and the custom was kept up till the year 1721, when the male line of that house became extinct; a house in which the meetings are said to have taken place is still remaining..