The following reign marks a period of great constructive activity at the Tower. The new monarch was one of the foremost military engineers of the age; and when we consider the valuable experience in the art of war which he had already gained, in the decade prior to his accession to the throne, in conducting (while Count of Poitiers and Duke of Aquitaine) various sieges of the castles of his rebellious barons in those provinces, it seems improbable that he would have been satisfied to leave the Tower in the condition it then was, with a keep standing in a small inner ward, enclosed by a plain stone curtain wall, devoid of any projecting towers, unless perhaps the base of the Hall tower, and the Cold Harbour Gate (see plan), and a large outer ward, only enclosed by a wooden palisade and ditch. Richard must have been well aware of the enormous increase to the power of effective defence conferred by salient or boldly projecting towers flanking with their fire the curtain walls, which in England, at any rate, were then somewhat of a novelty. At this time the Tower was extremely defective in this respect, its great need being not for mere repairs, but for effective modernization as a fortress. Before embarking upon the hazardous enterprise of the third Crusade, Richard left his trusted Chancellor, William Longchamp, to carry out an extensive series of new works at the Tower, all of which were probably from the designs of the sovereign himself. In his valuable monograph upon the Tower,[24] the late G. T. Clark, F.S.A., has fallen into a strange error as to the actual amount expended upon works there during the earlier years of the reign of Richard I., which he states "do not show above one or two hundred pounds of outlay." When this rather dogmatic assertion is tested by reference to the existing documentary evidence of the Public Records, its glaring inaccuracy is at once apparent; indeed, it might fitly serve as an illustration of Pope's well-known lines: "A little learning is a dangerous thing, Drink deep, or taste not the Pierian spring." The Pipe Roll of 2 Richard I. discloses an expenditure, "ad operationes turris Lundoniae," amounting to no less than L2,881 1s. 10d., in itself a sufficiently large sum, but one which, when multiplied twenty-fold in order to bring it up to its present-day value,[25] is increased to L57,621 16s. 8d. of our modern money! The custody of the Tower was entrusted by Longchamp to one of his dependents, William Puinctel, who seems to have acted as Constable and superintendent of the new works, according to the Pipe Roll of 2 Richard I.