The baron spent his whole time, ever since the decision come to by his nephew, with the master of the works, Alain of Troyes; while the workmen first called in cleared the ground and levelled the Roman ruins, and quantities of stone, sand, gravel, and timber were brought in, and the ditches and trenches for the foundations were excavated by the forced labour of the tenants. The baron designed to erect opposite the plateau (the point of attack) a great front, slightly convex, to screen the projections, W. He wished to have a wide barbican in the middle of this front, in which to collect the troops intended for sorties, and to shelter them in case of retreat. He had observed that in all the good defences erected by the Christians in Syria the entrances were so disposed that the assailant was obliged to present his right flank to the defender--with good reason, since the left is protected by the shield or buckler. The position of the gate, C, of the castle had been the subject of considerable study and discussion on the part of the baron and his master of works. The latter wanted to place it parallel with the front, but the baron insisted on its forming a decided angle with the entrance of the bailey. The master of the works urged that the left-hand tower of this gate, G, would then form a projection insufficiently defended, and open to attack; but the baron maintained that if the besiegers endeavoured to attack or mine this tower, they would be commanded obliquely by the tower, R; that by giving sinuosities to this front of the castle all points of the bailey would be commanded; that the principal gate was thus well masked; that nothing more would be needed than to give a considerable thickness to the walls and a greater diameter to the entrance towers; and lastly, if the enemy succeeded in reducing the projecting tower on the right hand, a barricade might still be raised from S to T, and the defence prolonged, with the favourable consideration that if this tower of the salient were thrown down, the other would remain intact and would command the breach. The postern, H, was also the subject of lengthened consideration on both sides. This postern was necessary to secure the provisioning of the castle without encumbering the main entrance. Placed near the angle tower, U, which the enemy could not attack because of the steep escarpment of the plateau, the postern was well protected by that tower; moreover it was to be surmounted by a quadrangular work with double portcullis and double doors; lastly, a _braie_,[20] X, defended its approach. It was agreed, moreover, that the great central habitable part of the castle, erected on the remains of the square Roman towers, should be crenelated, and should command the curtain, and consequently the two entrances. Wells existed or were sunk at _p_.