The keep appears to have been a square of 53 feet, and although about 9 feet of it are buried in earth and rubbish, it still rises to about 90 feet. Rather more than the outer or eastern half has been blown up, and has fallen into the ditch, and what remains has suffered much from alterations and additions. It is built in rubble of a very ordinary description, but with quoins and dressings of ashlar. The plinth, if one there be, is of course concealed. The walls are plain, 9 feet thick, having neither string nor set-off, and but one low pilaster buttress, which rises to the first floor only, and is placed upon the west end of the north wall, to give strength to an interior stair. At the two remaining angles are nooks, but not intended to carry shafts or beading.
The original tower was composed of a basement and first floor, about 70 feet high, or, as now seen, 60 feet. There remains within, against the west wall, a not very high-pitched weather-table, which shows, as at Porchester and Richmond, where the roof abutted against the wall as a gable. The wall was carried all round, high enough to conceal the roof. The west angle contains a well-staircase, which rose from the basement to the first floor. The door into the basement is buried, but the line of the steps in the wall points downwards. A breach has been effected in the west wall exposing the staircase, and seems to occupy the place of a loop.
In the west wall of the basement are two acutely-pointed recesses, terminating in square-headed loops; and in the south wall is a doorway, of 5 feet 6 inches opening, also under an acute arch. It is possible that this basement was vaulted, though it is more probable that the covering was of timber.
The first floor was originally lighted by three windows, in early pointed recesses, of different sizes and heights, and above the central recess, which was placed lower, to give place for it, are a round-headed recess and a window, placed in the angle of the gable. The three lower windows have been replaced by three lancets, and the recesses reduced in height and proportion to suit. The later arch is handsomely ribbed. It is uncertain how the first and main floor was covered over. In the north wall are seen the springing-stones of three ribs, evidently part of a vault; but near them is a short table, with four corbels, possibly connected in some way with the stair-entrance. Also there are fragments of two ribs in the west wall, so that the arrangements of the vaulting are obscure. The ribs mentioned are plainly chamfered, and may be early English, or later. An addition of about 30 feet has been made to the original keep, giving it an upper or second floor. In the west wall of this addition is a pointed window in a segmental recess, resting on the old masonry. In the north wall is another pointed window and a fireplace. There is a loop towards the south; but this part of the wall, both inside and out, is obscured by ivy. In the wall of this floor, cutting the line of the windows, is a corbel-table, the corbels cut somewhat into the shape of heater shields. This must have supported the roof, but have interfered seriously with the windows. How this story was reached does not appear; probably by a well-stair in the wall, now destroyed, a point which could, no doubt, be ascertained by uncovering the fragments in the ditch. The upper wall seems as thick as that below; and it is curious that there are no traces visible of mural galleries or chambers.
The battlements remain perfect, so far, at least, as are the walls they crown. The embrasures are of moderate size, and the merlons broad, and the running moulding is carried round the whole. At each angle is a square turret, rising about 10 feet above the curtains. These turrets rest upon a light bracket outside, and each of the outer faces is flanked by two light, slender buttresses, in tabernacle work, resting below upon brackets, and, no doubt, once ending above in delicate finials. In each face is a single embrasure. Of course, all these are additions.
The question of the entrance to this keep is obscure. There remain three doors, any one of which would serve. That on the ground floor to the south; a small round-headed door at the first floor level to the north; and a third door, in the same wall, a little lower down, leading into the well-stair. There are, however, indications that none of these was the real entrance. Against the south wall are traces of attached masonry, probably of a forebuilding, containing and covering the entrance, which in that case would have been in the south wall near the east end, a part now destroyed. The staircase seems to have commenced against the south-west end of this wall, and to have passed over the present door, which probably, as at Rochester, opened into a cell below the staircase of the forebuilding. This conclusion is strengthened by the presence of seven holes in the keep-wall at the rampart level, evidently to carry a brattice commanding the staircase below. Also, high up in the same wall, there projects a mass of ashlar, which may very well have been part of a machicolation, overhanging the door at the stair-head: arrangements similar to these are not uncommon in keeps of this pattern. Of the other doors the small round-headed one may very well have opened upon the ramparts as at Clitheroe; and that which is let into the well-stair, now closed and converted into a loop, looks rather of a Decorated character, and may be an insertion, and may have led into some annexed building now destroyed. At the period when this tower was built there was no longer that extreme caution in allowing no more than one entrance to the keep.
It would seem that the original keep was late Transition or pointed Norman, and therefore might well have been built, as supposed, by Robert de Ros, surnamed Fursan, who held the lordship from 1184 to 1226, and probably completed the work before 1200. Then came the alteration in the first floor in a most decided early English style, and therefore probably by Robert de Ros, Fursan’s grandson, who married the heiress of Belvoir, and flourished between 1257 and 1285. Then followed the addition of the upper story, and of the battlements and turrets, all rather late Decorated. This might well be the work of William de Ros, who held Helmsley from 1317 to 1342, to whom, in 1337, was granted the tower built by Edward II. in London, near Baynard’s Castle, and which seems to have stood on the bank of Fleet-ditch, where some ancient foundations were recently laid open in the formation of the new street. This he was to hold as appendant to his Castle of Helmsley.
The domestic buildings standing opposite to the keep are composed of two blocks. One a square mass of great height, and with walls of considerable thickness, has traces of transition Norman or early English work, but has undergone alteration in the Decorated period, and finally in that of the sixteenth century. The other or northern building may be on early foundations, and probably is so, but its fittings are of the sixteenth century, and probably the work of the Earl of Rutland, whose armorial bearings are embossed in plaster on a deep cornice and on the panelled ceiling, all now in the last stage of decay.
The northern gatehouse, and any structure that may have stood upon the smaller barbican, have disappeared utterly from sight, though probably their foundations could be laid open. To the south there is more to be seen. The inner gatehouse indeed is ruined, and nothing is visible above the rubbish save the outline of the western jamb, which shows a portcullis groove and rebate for folding-gates.
The outer gatehouse and its barbican form a very remarkable work. This barbican is, as has been stated, an expansion of the bank which surrounds the inner ditch. It is here above 80 feet broad, and long enough to cover completely the southern front of the place. The gatehouse, like that behind it, is much nearer to the east than to the west end of the work. It is composed of two small round turrets, and two large drum-towers flanking the portal. On either side of these extend the curtains, which terminate in a pair of large drum-towers, which flank and close the outwork.