Castell pen y coed is in a strong position, placed within the angle made by the junction of two small streams that eventually fall into the Tav, on the northern boundary of the parish. One of the streams flows almost directly north; its left bank rises abruptly for about 200 feet, and at the top is placed the camp. The other stream makes a wide sweep until its direction becomes almost east and west before it unites with the first-mentioned brook at a point about 500 yards to the north of the camp. The defences consist of three strong banks, with two intervening ditches. They face directly to the west, protecting a somewhat small area of ground in front of the sharp slope to the river. It is evident that escape in face of disaster must have been by a rush down the hill, a dangerous operation, with a stream, however small, at the foot, especially in wet weather. The innermost bank rises to a height of 15 feet, and is of massive construction; the two other banks are about 8 feet high. The ditches are each about 12 feet in breadth. The entrance appears to have been at the northern end of the banks, and probably had a straight course across the different ditches, but it has been too much disturbed to admit of certainty. Visited, 16th May, 1912.

NOTE: This earthwork 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 6th century."
Source: RCAHMW Inventory for the County of Carmarthen, 1917, p.38, no.130.

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.

See also nprn 404552 for possible location of the battle in Glamorgan.
B.A.Malaws, RCAHMW, 05 July 2006.