Since the rise, during the last twenty years, of numerous county archæological societies, castles have received more attention; but no distinct work has appeared upon English castles, though many of the most remarkable are noticed by Mr. Parker in his excellent works on domestic architecture. More recently has appeared the book of the late Mr. Wykeham Martin upon his ancestral castle of Ledes, a work not only well illustrated and furnished with an excellent ground-plan, but in which the architecture and arrangements of the fortress are treated in a scientific manner, and his conclusions supported, in many instances, by original documents. England contains many curious and some grand examples of military architecture; but that insular position and those industrious habits which have given her internal peace have not been favourable to the erection of fortresses of the larger class: for these we must pass to the Continent, and especially to France. In France not only were the works of imperial Rome of a grand and substantial character, but they were adopted and employed by the people after the fall of the empire, and both Franks and Visigoths, unlike our English Saxons, practised the arts of attack and defence upon Roman principles, and remodelled the older works to meet the later circumstances of the period. In the southern provinces, especially, are still to be found castles and fortified towns such as Tholouse, Narbonne, Beziers, and Carcassonne, where the old Roman circumvallation has been preserved, and may still be recognised amidst the additions and alterations of succeeding ages. Like the Romans, their successors made use of earthworks and of timber both for attack and defence, and for permanent works employed masonry of a very Roman character. Such accounts as have descended to us of the great sieges of the Middle Ages show that the machines and methods in use were those handed down by tradition from Rome, many of them being such as Cæsar employed, while others were the same as those sculptured on the column of Trajan or described by Vegetius. Mines and countermines, battering-rams, balistæ, catapults, the cat, the mouse, the sow, and a large family of devices for reaching under cover the wall to be undermined, were all derived from Roman warfare, and were employed, if not with the skill and discipline of Rome, with a degree of vigour and boldness that was scarcely less effective.