In considering the limited and very inconvenient accommodation afforded by a Norman keep, it should be remembered that it was not meant for a residence, save during an actual siege, and that at such times it often only received the baron’s armed tenants, and not his mercenaries. Indeed, the builders of some of these keeps seem to have mistrusted their own troops as much as they feared those of the enemy. The staircases and galleries are often contrived quite as much to check free communication between the several parts of the building as between its inside and its outside. Further, the excessive jealousy in guarding the entrance, the multiplied doors, the steep and winding staircases, the sharp turns in the passages, although they helped to keep out an enemy, or, if he got in, placed him at a disadvantage, also rendered impracticable the rapid re-entry of the garrison, so that if the court or outer ward were taken by assault, the defenders had scant time to retire into the keep, which was thus liable to a coup de main. Otherwise, with a sufficient and faithful garrison, and ample provision and military stores, a Norman rectangular keep was almost impregnable, so great was its passive strength. Its windows were too small or too high for their shutters to be reached by fire-balls, and its walls were too thick to be breached or mined, if properly defended from the summit. This, indeed, was the true method of defence. An ordinary loop in a thick wall, however widely splayed, admitted of but little scope for an archer, or space to draw his bow. The lower loops were entirely for air, not for defence. Higher up, with larger windows, a bow could be used with advantage, but there were no flanking defences, for the angles had no considerable projection, and the shoulders, or lateral faces of the pilasters, were not pierced. With military engines for throwing heavy stones and masses of rock from the roof much might have been effected, but in the early keeps this was not contemplated, and probably not to any great extent in the later ones. An arrow shot from a battlement 50 feet or 70 feet high would lose some of its force in the descent. Of the siege of Rochester certain particulars are on record, and the account of the operations of the besiegers is confirmed by the evidence afforded by the existing keep. Rochester keep stands but 10 feet or 12 feet from the south-east angle of the outer wall, the angle of the keep corresponding with that of the wall. The angle of the wall and part of the adjacent curtain have evidently been removed and rebuilt, with the capping tower, in a later style. Opposite and behind this newer work, the lower part of the angle of the keep has also, at some remote time, fallen away, and with it a few yards of the adjacent sides. These parts have been rebuilt in a rude and slovenly manner, and the junction of the old and new work is very evident. This keep was built about 1130, and besieged by King John for three months in 1215. Military engines produced little effect upon it, but a mine was opened which, says Wendover, first brought down the walls and then a part of the tower. This is what we now see. The keep seems to have been repaired in haste at once, the outer wall probably not till 1225, when Henry III. spent considerable sums upon the castle, and the capping-tower of the curtain is of that date. The attack by sap was the only one to be employed against a rectangular keep, and was rarely practicable. Where, as was often the case, the keep stood upon a rock, the running a mine below it would produce no effect. Where this was not the case, the foundations of the wall were so broad and so solidified as to stand even when much of the soil beneath them was removed. At the White Tower, for example, when it was found convenient to bring a railway from the river quay into the base of the keep for the shipment of stores, about 20 feet of solid masonry had to be cut through, and much earth removed, and this, with every aid, was found to be a very tedious and expensive operation. The defence of such a keep was its passive strength alone. The loops were nothing in its defence; the roof being on a slope and of shingle would support no military engine and no great store of stones or heavy missiles. The narrow doorway did not allow of a sally in force, and when seriously attacked the garrison had no resource but to trust to the thickness of their walls, their ample supply of water, their magazines of provisions, and thus patiently to await relief.

Such are the details of the rectangular Norman keeps, of which we have in England about fifty extant or well-recorded examples, dating from the year 1078, when the White Tower was begun, to about the year 1180, to which may be attributed the keep of Helmsley.

LIST (APPROXIMATIVE) OF RECTANGULAR KEEPS IN ENGLAND.

CHAPTER X.

OF THE SHELL KEEP.

WHILE of the rectangular keep there remain many, and some very perfect, examples both in England and Normandy, the SHELL KEEP, though once the most common of the two, has rarely been preserved, and is seldom, if ever, found in a perfect or unaltered condition. There is a difference of opinion as to the date of the introduction of these keeps, whether a little before or a little after the other type. The shell keep, being invariably connected with early earthworks, might be supposed to be the older form; and Arundel, the only castle mentioned in Domesday as existing in the time of the Confessor, has a shell keep; but a tolerably close examination has failed to discover, either at Arundel or elsewhere in England or in Normandy, any masonry of very early character, probably none that can safely be attributed to the eleventh century. The fact seems to be that the early timber structures, which are known to have been erected originally on the moated mounds, were found to be very defensible, and so were retained by the Norman lords until they were able to replace the timber by masonry. The rectangular keeps were either on new sites, or on sites not defended by very strong earthworks, so that their construction, from the first, was in masonry, and thus it came to pass that the shells of masonry, though always connected with the older sites, were of later date than the solid towers. Even at Durham, a castle recorded to have been built by the Conqueror, and of which the keep must always have been on the present mound, though the chapel and connected buildings may be his work, the shell keep contains no Norman masonry; and if, as is to be supposed, there was once a Norman shell, it was probably the work of one of the Conqueror’s sons, or even of Henry II.

A shell keep is always placed upon a mound, either natural or artificial. Of those on natural hills, the most considerable are Belvoir, Durham, and Lewes, but the masonry of the two former is not original, though built upon the old lines. Dunster, the Tor of the early Lords Mohun, has been examined, and the only trace of its keep is a fragment of a drain. Montacute, where the hill is wholly natural, has also been cleared of masonry. But by far the larger number of these mounds are either wholly artificial, or of a mixed character.

In plan and dimensions these keeps are roughly governed by the figure of the mound on which they stand. Most are polygons of ten or twelve sides, not always equal. Some are circular, others polygonal outside and circular within. Others are slightly oval, others more complex in plan. York, for example, approaches to a quatrefoil, 64 feet by 45 feet, and this seems to have been the plan of the long-since destroyed keep of Warwick. Their diameter is rarely less than 30 feet, and seldom exceeds 100 feet.