The occupation by the Normans of the valleys of the Wye and the Usk no doubt served to protect the exposed flank of Monmouthshire, but beyond the Rhymny in Glamorgan this protection ceased, and the hill territory of Glamorgan contained a native population ever ready to assist their countrymen, who frequently invaded that Lordship from the north-west. The Norman settlers all dwelt in the strip of open and more fertile land from six to twelve miles in breadth that intervened, like the Concan of Western India, between the mountains and the sea, where the remains of their castles are placed so near together as to raise a question as to whence the inhabitants derived their means of subsistence. The chief castle of the Lordship was that of Cardiff on the Taff; but the lord also held castles at Dinas Powis, Llantrissant, Kenfig, and by an early acquisition, at Neath, all which may be presumed to have been intended for the general protection. Cardiff, upon the “via maritima” of the Romans, is a very remarkable fortification. It is rectangular, protected on three sides by a very high bank and ditch, and on the fourth, towards the river, by a very strong wall. In one corner at the river end is a large moated mound still bearing the Norman keep, and which stood upon the line of a second wall now destroyed, by which that end of the area was cut off and protected from the rest. The analogy of this work with those of Tamworth, Wareham, and Wallingford, and in some degree with Leicester, is remarkable. It also has some points of resemblance to Hereford. Dinas Powis is a small oblong enclosure of the type of Dinas Brân and Dolforwin, probably of Norman date. It occupies the top of a rock in the gorge of a deep valley, and must have been strong against any mere assault. Llantrissant Castle was of rather larger dimensions. It stood, and indeed a fragment of it still stands, in a notch in the hill high above the plain and many miles from the sea. Kenfig, which stood upon a brook near the sea coast, has been completely swallowed up by blown sand, “consumptum per sabulonem,” and only a fragment is now visible. Neath, the most exposed castle in the whole county, was founded by De Granville, said to be the brother of Robert Fitz Hamon. Save those of the Lord the only castle in the Lordship held by a public functionary was that of the Bishop at Llandaff, which seems to have been always a place of strength, though the gatehouse and enclosing wall still remaining are probably as late as the reign of Henry III. or Edward I.