136 ROMAN FORTIFICATION. 



neglected and forgotten, had been as often recovered from books.* 

 Vegetius hoped his treatise on military institutions might be means 

 of reviving it again. He evidently wrote with that object in view ; 

 he proposed no novelties ; he explained and urged the adoption of 

 the ancient methods, which had been proved in past ages, and had 

 the recommendation of the highest military authorities of those 

 ages. If this is borne in mind, the peculiar value of the two books 

 to us in our investigations about the walls of Dorchester will be 

 perceived. 



Yitruvius, who had been an engineer officer in the army of Julius 

 Caesar, wrote his book about B.C. 25. Vegetius dedicated his 

 treatise to the Emperor Valentinian ; it must in consequence have 

 been written about A.D. 370. In points, therefore, on which 

 Vitruvius and Vegetius are in accord we have practically an 

 unbroken chain of evidence as to the manner in which the Romans 

 fortified their towns between the years B.C. 25 and A.D. 370, and 

 if, on examining the Roman works about Dorchester, we find they 

 do not accord with the descriptions given by both these writers, we 

 must conclude that either from the nature of the soil, or from some 

 other peculiarity, it was not advisable to carry out the fortifications 

 in the usual way ; or that the walls here were originally built in 

 accordance with the general rules of Roman fortification, but that 

 the details, which do not now appear, have been destroyed at some 

 subsequent period. 



At first sight it might be thought that Dorchester was the site of 

 a camp constructed by Vespasian when he subdued the Britons who 

 lived in these parts, and that in later years the ditch was deepened 

 and a wall built upon the rampart in the place of the palisade ; 

 and, thus strengthened, the spot was adopted as a site for the town 

 Durnovaria. 



* Haec ex TISU librisque antea servabantur, sed omissa diu nemo 

 quaesivit, qui vigentibus pacis officiis procul aberat necessitas belli. Sed 

 ne impossibile videatur reparari disciplinam, cujus usus intercidit, 

 doceamur exemplis. Apud veteres ars militaris in oblivionem saepius 

 venit, sed prius a libiis repetita est, postea ducum auctoritate firraata 

 (Lib. iii. c. 10.) 



