The earlier alterations at Chepstow, and more particularly the oratory attached to Martin’s Tower, and the columnar corbels in the keep, may be cited as of an earlier date than Caerphilly, having been evidently placed there before the decline of the Early English style.
The internal evidence of the building, which would place its date about the end of the reign of Henry III., agrees with the evidence of records cited hereafter, in which the castle is referred to, in the year 1272, as having been lately erected by Gilbert de Clare, Earl of Gloucester and Hertford.
Before this period, mention is occasionally made of the castle of Senghenydd, which, from its having been taken, retaken, and more than once utterly destroyed, was evidently a place much contested, but of no great magnitude or passive strength. After the erection of Caerphilly, Senghenydd Castle is not again mentioned. It is therefore not impossible that Senghenydd Castle was a rude fortification of timber and undressed stone, upon the peninsula afterwards occupied by Caerphilly.
Caerphilly having then certainly been founded by Earl Gilbert a little before 1272, the question arises as to whether the whole of it was then built.
The inner ward, its curtains, bastions, gatehouses, with all their contents and appendages, are of one date. The south wall was always of its present height, and therefore always intended to support the roof of the hall, the walls of which are bonded into it. The gatehouses are evidently part of the original plan, and the long windows of the staterooms, and those of the oratory in the inner gatehouse are, in their form and mouldings, precisely similar.
It appears that the curtain connecting the north-west bastion tower with the west gatehouse was originally as low as the northern curtain, but that a sort of gallery, and its superincumbent rampart, have been added. A cluster of buildings has also been added on the outside of the south curtain, at the angle formed by its junction with the south-west tower.
The general design of the middle ward, and most of its buildings, are clearly of the date of the inner ward. The western gatehouse, however, appears to be of somewhat later date; the false machicolations, the holes for the portcullis chains, the chimneys rising above the parapet, and the less durable character of the masonry, seem to indicate this. The walls, moreover, by means of which this gatehouse is connected with the curtain of the inner ballium, though of the same age with the former, are not bonded into, and are separated by fissures from, the latter—a tolerably sure indication of difference of age.
It is not improbable that the whole exterior line of defence on the east, and the horn-work on the west, were the last parts of the castle completed. They form, however, parts of the original design, since, had the ground on which they stand been left unoccupied, the castle would not have been tenable.
With respect to the redoubt, it is perfectly evident, from its appearance, that it was thrown up, not only when gunpowder was in general use, but when the science of fortification was pretty well understood. It seems, like the earthworks at Donnington and other castles, to be of the age of Charles I.
The injuries received by this castle are similar to others at Corfe and elsewhere, known to be referable to the same period of civil strife in which the battle of St. Fagan’s, and the occupation of Cardiff, prove the men of Glamorgan to have taken an active part. Nothing, therefore, seems more probable than that the redoubt should have been thrown up hastily by one party for the defence of the castle, and that the dismantling of the whole should have been perpetrated by the other, to prevent such a defence being practicable in future. Though history has afforded no clue as to the one of the contending parties to which either proceeding is to be referred, there can be no doubt but that the blowing up of the towers was the work of the Parliament.