Page:Medieval Military Architecture in England (volume 1).djvu/153

 TJie Rectangular Keep of a Norman Castle. 137 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, ad- mitted 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 battle- ment 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 1 1 30, 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 HI. 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 con- venient to bring a railway from the river quay into the base of the keep for the shipment of stores, about 20 feet of solid