On the first edition 25in map of 1877, at the given NGR approximately 1km southwest of Pencoed, Glamorgan, is an annotation 'Site of Battle AD733'; on second and third editions, 1899 and 1919, the date is amended to 'AD721.'
In or about 722, the Welsh won a victory against the Mercians in south Wales, at a Pencon or Pencoed, a place not yet identified.
Source: J.E.Lloyd, A History of Wales, 1954, vol.1, p.197.
721: The Britons prevailed in the battle of Pen-coed in Deheubarth [Carmarthenshire].
Source: Thomas Jones, The Chronicle of the Princes, 1955, p.5.
"Castell Pen-y-coed hillfort [nprn 304193; at grid ref. SN 2453 1278 near Llanddowror in Carmarthenshire] has been suggested as the possible scene of the battle of Pencon or Pencoed, said (Annales Cambriae and Brut y Tywysogion) to have been fought in the sixth century." Source: RCAHMW Carmarthenshire Inventory, 1917, p.38, no.130.
B.A.Malaws, RCAHMW, 05 July 2006.