Saint Brynach was a 6th century Irishman who first landed in Wales at Milford Haven, where he was beaten for resisting the advances of a local nobleman's daughter. He then travelled to the Gwaun Valley and freed Pontfaen from evil spirits whose howling had made the village uninhabitable.
The saint is most associated, however, with the village of Nevern (Nanyfer in Welsh), Pembrokeshire, where his hermitage was located. Along with St. David's Cathedral (St. David's, Wales) this is one of the earliest sites in Britain used continuously for Christian worship. (Wales remained Christian after England was occupied by pagan Anglo-Saxons.) The church of St. Brynach in the village is believed to stand on the site of the saint's hermitage. While the current church building is of more recent construction, the antiquity of the site is indicated by the presence of a number of ancient inscribed stones in the churchyard and the church itself dating from the time of the saint. The Vortiper stone, which stands just outside the church entrance and has inscriptions in both Latin and Irish Ogham scripts, has been dated to c.466 to c.533; another dual-script stone has been re-used as a lintel inside the church, and at least one more Latin-inscribed stone can be seen on the outer fabric of the structure. The story associating the magnificent Celtic cross outside the church with Ss. Brynach and David (David is said to have carried the cross to Brynach as a gift), is, however, inaccurate as the cross dates to sometime between the 11th-13th centuries—at least six centuries after the saints.
St. Brynach himself lived an austere life of constant fasting and prayer. Wild beasts became tame for the saint, and his holiness was so great that he communed with angels on the summit of nearby Carn Ingli, the Mountain of Angels (also the site of a pre-Christian hillfort), which dominates the local landscape. A twelfth century hagiography, the Vita Sancti Bernachius exists, written by an anonymous author in the district of Cemaes, which includes Nevern.