T. E. Lawrence’s Undergraduate Dissertation – Page 216

The best solution of the problem (which was not discover- ed till after polygonal towers had been tried and found want- ing) proved to be the circular keep, standing isolated and self-contained in a most of its own. Philip Augustus built multitudes of these, and Richard of England a few: finally Enguerrand de Coucy set the seal of his approval upon it. One of Richard's keeps, at Montreuil Bonnin(77) near Poitiers is almost certainly earlier than his Crusade. The entrance is 30 feet in the air, and the staircase is straight instead of winding. The contemporary outworks and ditch show that Richard did not despise such helps to perfection. A nearer example of an eccentric circular keep will be found in Conisborough in Yorkshire. The shell-keep alternatives to the large square tower are wonderfully numerous, but that at Gisors is so very well known and so typical that there is no need to give any des- cription of them. It was built by Henry II (xc) but since his time the large door has been pierced in the wall, and the ungainly turret crushed in between two of the buttresses of the octagonal tower: this octagon has itself been rebuilt from the first floor level. A similar instance of shell- keep and tower within is at Evrès near by. The keep of Gisors is a small one, standing as it does on an artificial mound, but there is one at Pujols,(cy) on the Dordogne near Bordeaux which encircles the top of a natural hill, and is of very