Rufus, however, with far more energy than his brother Robert, had also the popular feeling on his side, which enabled him to make head even against this powerful combination. He laid siege to Pevensey, and took it after a seven weeks’ siege. He then assailed and took Rochester, and finally Tonbridge, held by Gilbert Fitz-Richard, the consequence of which success was the banishment of Bishop Odo. Robert Mowbray was beaten back from before the walls of Ilchester Castle, now utterly destroyed; and Bishop William was forced to surrender Durham. Carlisle, wasted by the Danes in 877, received from Rufus a castle and a keep, now standing; and Newcastle, similarly provided in 1080, also retains its keep, and a gatehouse with some traces of the exterior wall. In 1098 Malcolm of Scotland, the husband of St. Margaret, was slain before Alnwick, then better known as Murielden; and Mowbray was driven from Tynewald Castle back upon Bamburgh, which seems to have been finally taken by means of a “malvoisin,” which in this instance was evidently an entrenched camp thrown up to the west of the castle, and employed probably as the headquarters of a blockade. In this reign also the conquest of South Wales was completed, and the foundations laid of a chain of castles from Gloucester and Hereford to Pembroke, the main links of which were Chepstow and Abergavenny, Caerleon and Cardiff, Builth and Brecknock, Caerkennen, Caermarthen, Cardigan, Tenby, and Carew. How far these Welsh castles were at once constructed of masonry is uncertain. Besides Chepstow, two only, or at most three, and those subordinate, Ogmore, Penlline, and Newcastle, exhibit decided Norman features; but however this may be, neither Fitz-Hamon, Newmarch, nor Arnulph of Montgomery were likely, in the face of foes so formidable, to be satisfied with defences in any way inferior to the strongest of that day. The reign of Henry I. was prolific in castles. It is probable that to him is due the greater number of our extant rectangular keeps, by the construction of which he carried to completion the plans sketched out by his father, which his brother had been too busy and too much pressed to take in hand. In this reign, especially between 1114 and 1121, most of the Welsh castles were completed. Bristol and Cardiff castles were the work of Robert Earl of Gloucester. Bishop Roger of Salisbury built Sherborne, Salisbury, the Devizes, and Malmesbury; and his brother, Alexander of Lincoln, Sleaford and Newark. “Castella erant crebra per totam Angliam.” Most of these were great and strong, very different from the hasty and unlicensed structures of the succeeding reign.