Henry III. found his realm over-built with castles, and amongst the vigorous exertions by which William Marshall and Hubert de Burgh restored the royal authority should specially be recorded the sieges of Biham and Bedford castles, two very strong places. The Close Rolls show the extent of the preparations for these sieges. The sheriffs of the whole Midland and westward to the Forest of Dean are directed to provide and forward materials and munitions of war. Carpenters, smiths, quarrymen to dress stone bullets, miners and engineers, are placed under requisition, and from all sides are ordered timber, stone, lead, cord, cable, chain, iron bars, balistæ, catapults, mangonels, crossbows of wood and horn, targets, quarrels, arrows, slings, hides to cover the malvoisins, and mining tools. Both castles were stiffly defended, and both were taken. Of Biham no trace remains; of Bedford a fragment of wall and a mound, reduced almost to a mole-hill, still shows that Henry’s work was not done negligently. Towards the end of the reign occurred a still more famous siege, that of Kenilworth. Here, as on the former occasion, Henry commanded in person, and the celebrated “Ban of Kenilworth” shows how complete was his victory. Henry also conducted a campaign in South Wales in which the castles of Monmouth, Usk, Chepstow, Caerleon, and Cardiff played important parts—castles calculated to prove a sharp thorn in the side of an English prince, and to render a uniform and just government impracticable. Henry is not certainly known as the founder of any important English castle, but he added to and restored very many. Skenfrith near Monmouth dates from a little before his time; but Grosmont and White Castle, the two other members of the great border trilateral, may be of that reign. Henry, no doubt, was a great builder, and very princely in his operations; but his works as regards castles were chiefly shown in building, repairing, and adorning the walls and windows of the royal lodgings, halls, and chapels in the royal castles, works which were in all cases carried on outside the keep, within the middle or outer wards, and which in most cases have long since been swept away. Henry found his castles built to his hands, and had no opportunity of introducing any specific style or type of military work. White Castle is a mere pen or enclosure, with high walls and mural towers, though its earthworks, probably of earlier date, are on a great scale.