To inform the consideration of The Inventory of Historic Battlefields in Wales , documentary and historical research was commissioned on the 1081 battle of Mynydd Carn and the resulting research report provides a detailed overview (Border Archaeology).

The battle of Mynydd Carn represented a turning point in the medieval political history of the Principality; the established order represented by Trahaearn ap Caradog in Gwynedd, Caradog ap Gruffudd in South Wales and Meilyr ap Rhiwallon in Powys were overthrown and killed by Rhys ap Tewdwr of Deheubarth and Gruffudd ap Cynan, an exiled heir of Gwynedd. As a result Rhys ap Tewdwr secured his position not only as ruler of, but also as the leading Welsh lord in, South and West Wales.

The principal source for the details of the engagement remains the Vita Griffini Filii Conani , supplemented by important references to the battle in two early Welsh poems, an elegy to Trahaearn ap Caradog (composed in the form of a prophecy after the event) and an elegy to Gruffudd ap Cynan, both apparently composed by the Welsh bard Meilyr Brydydd (although his authorship of the former poem has been disputed) and by the brief entries concerning the battle in the Breviate and Cottonian Chronicles and the Brutiau.

The site of the battlefield of Mynydd Carn remains undetermined, although all the sources appear to agree that the battlefield was located on a hilltop/mountain site marked by a prominent cairn. The available documentary evidence and modern scholarly opinion places the location of the battle somewhere in northern Pembrokeshire within the Cantref of Cemais (possibly in the vicinity of the range of hills between the north Pembrokeshire coast and the Afon Gwaun represented by Mynydd Carningli, Mynydd Llanllawer and Mynydd Dinas).

RCAHMW (Battlefields Inventory), Jan 2017

Bibliography

Border Archaeology, Mynydd Carn (1081): Documentary and Historical Research Report (2009).