The remains of St Brynach's Church stand within a polygonal churchyard (only half of which still survives) adjacent to the foreshore in the coastal valley of Cwm-yr-Eglwys. The church site may be early medieval in origin and may be associated with nearby Castell Iron Age defended enclosure (NPRN 304399). Two undated cist graves were noted under the floor of the church in 1981. Bryn Henllan cist cemetery (NPRN 422379) lies some 800m to the south-west. The earliest surviving document for the parish and possibly the church is the Norwich Taxation of 1254 which notes `dispensation, at the request of the cardinal of the Holy Apostles, to Maurice to hold the churches of Dinas and Nambeude, together with that of Hebernat; the value of all three not exceeding 12 ? marks.?

Most of the church building and the seaward side of the churchyard were washed away in a storm in October 1859. A drawing by H Gastineau c 1825 is believed to show the church's final form ? a nave measuring 36ft x 14ft orientated east-west, with a chancel measuring 18ft by 12ft on the eastern end, and a transept measuring 18ft x 12ft adjoin the southern wall. Above the west door, there was a bell-cote. The architectural history preserved in the building's fabric was lost in the Great Storm of 1859. Cwm-yr-Eglwys lies exposed to the northeast and the storm's resultant surge of 15ft (4.5m) above normal high water carried away the side wall and roof. In the Haverfordwest and Milford Haven Telegraph by Owen Edwards, Coroner to the Northern Division of Pembrokeshire, he described `the sea washing right through it. The churchyard is much injured. Several houses are damaged; one house in particular is nearly destroyed?. To the east of the church, a schooner, the MATHILDIS (NPRN 272463), and a sloop were lost. Eight bodies were subsequently washed ashore or recovered from the cliffs. Two burials are recorded in the Dinas Burial register for 30th October ? `Unknown drowned in a shipwreck during a terrific gale Oct 25th 1859. Abode, both Cardiganish as supposed?. The upstanding remains comprise the west wall. Stone for the church have been incorporated into the seawall that defends it. Of note is an incised stone believed to have been part of the sundial.

Sources include:
Driver, T. 2007. Pembrokeshire: Historic Landscapes from the Air, RCAHMW, 153
Dyfed Archaeological Trust, 2003, Early Medieval Ecclesiastical Sites Project, Pembrokeshire
John Hughes, 2010, The Church of St Brynach the Abbot Dynas in Kemmeys, RCAHMW Collections

Maritime Officer, RCAHMW, September 2012.