"Gundulfus ... illis contulit beneficium ... _castrum_ etenim, quod situm est in pulchriore parte Hrovecestræ.... Regi consuluerunt [duo amici] quatinus ... Gundulfus, quia in opere cæmentarii plurimum sciens et efficax erat, _castrum_ sibi Hrofense _lapideum_ de suo construeret.... Dixerunt [Archiepiscopus et Episcopus] ... quotiescunque quidlibet ex infortunio aliquo casu in _castro_ illo contingeret aut infractione muri aut fissura maceriei, id protinus ... exigeretur.... Hoc pacto coram Rege inito fecit _castrum_ Gundulfus Episcopus de suo ex integro totum, costamine, ut reor, lx librarum."[983] Though _castrum_ is the term used throughout, Mr. Parker in his essay on _The Buildings of Gundulph_, 1863, assumed that a _tower_ must be meant, and wrote of "Gundulf's tower" in the Cathedral: "This is probably the tower which Gundulph is recorded to have built at the cost of £60."[984] So too, Mr. Clark wrote:— "As to his architectural skill and his work at Rochester Castle, ... the bishop [was] to employ his skill, and spend £60 in building a castle, _that is, a tower_ of some sort. What Gundulf certainly built is the tower which still bears his name.... It may be that Gundulf's tower was removed to make way for the new keep, but in this case its materials would have been made use of, and some trace of them would be almost certain to be detected. But there is no such trace, so that probably the new keep did not supersede the other tower."[985] Mr. Freeman guardedly observes:— "The noble tower raised in the next age by Archbishop Walter (_sic_) of Corbeuil ... had perhaps not even a forerunner of its own class. "Mr. Hartshorne showed distinctly that the present tower of Rochester was not built by Gundulf, but by William of Corbeuil.... But we have seen (see _N. C._, vol. iv. p. 366) that Gundulf did build a stone castle at Rochester for William Rufus ('castrum Hrofense lapidum' [_sic_]), and we should most naturally look for it on the site of the later one. On the other hand, there is a tower seemingly of Gundulf's building and of a military rather than an ecclesiastical look, which is now almost swallowed up between the transepts of the cathedral. But it would be strange if a tower built for the king stood in the middle of the monastic precinct."[986] Thus the problem is left unsolved by all four writers. But the true interpretation of _castrum_, as established by me above, solves it at once. For just as William of Corbeuil is recorded to have built the "turris" or rectangular keep,[987] so Gundulf is described as constructing the _castrum_ or fortified enclosure.[988] We must look, therefore, for his work in the wall that girt it round. And there we find it. Mr. Clark himself is witness to the fact:— "Part of the curtain of the _enceinte_ of Rochester Castle may also be Gundulph's work. The south wall looks very early, as does the east wall."[989]