LLANTHONY-ABBEY, a chapelry, in the Upper division of the parish of Cwmyoy, union, division, and hundred of Abergavenny, county of Monmouth, 10 miles (N. by W.) from Abergavenny. This place is distinguished as having been chosen by St. David, uncle to King Arthur, and titular saint of Wales, for his seclusion from the world. Finding here a solitary spot on the banks of the Honddû, among rocks, woods, and valleys, he built a small chapel, and made it a hermitage, where he passed many years, and which was afterwards unfrequented for several centuries: this chapel was called Llan-Dewy-nant-Honddû, or "the church of St. David on the Honddû," now corrupted into Llanthony. In the reign of William Rufus, Hugh de Lacy happening to follow deer into this retreat, William, one of his followers, was impressed with the wild solitude of the scenery, and, espying the chapel of St. David, resolved to devote himself here to the service of God: after passing several years alone, he induced Ernest, chaplain to Queen Maud, wife of Henry I., to become his associate, and by their united efforts another chapel was built, which was consecrated, in 1108, to St. John the Baptist. Soon afterwards, Hugh de Lacy founded a priory of Canons regular of the order of St. Augustine, also dedicated to St. John; and when riches poured in upon the establishment, a more magnificent church was erected. The remains of the abbey, built in the form of a Roman cross, and exhibiting a fine specimen of early English architecture, with some Norman details, are situated in the vale of the Ewyas. The living is a perpetual curacy; net income, £55; patron, the Bishop of St. David's.See Cwmyoy.