On Stephen’s arrival from Normandy, in 1137, he secured the castles of Bourne, Wareham, and Corfe, the two latter held by Fitz-Alured and Redvers. A second rising, in 1138, timed with an invasion by the Scots, turned in some degree upon the strength of the castle of Bedford, then including a pair of moated mounds on the opposite banks of the Ouse, of which one is entirely removed, and the other remains deprived of its masonry, and shorn of its fair dimensions. This castle was held by the sons of Milo de Beauchamp, its owner, and only surrendered after a long and severe siege conducted by Stephen in person, which terminated in a blockade. The defence was very able, and the surrender upon fair terms. Meantime David, linking the interests of Matilda with his own claims to the great earldom of Huntingdon, twice crossed the border in the spring of 1128, retiring as Stephen approached, but a third time returning in August. He took Norham, and much injured its superb keep, built by Bishop Flambard in 1121, a noble ruin which still frowns over the Tweed, and is rich in historical recollections. Bamburgh, Alnwick, and Malton were held for Stephen by Eustace Fitz-John. Parts of the wall and inner gate of Alnwick are of about this date; but Malton has disappeared, though the earlier Roman camp may still be traced. David’s progress was also checked by Clitheroe, a very strong castle, of which the Norman keep, one of the very smallest extant, crowns the top of an almost impregnable rock. At this period Stephen’s position was most critical. Against him, on the Welsh Marches, Talbot held Goderich and Hereford, while Ludlow and Dudley, Shrewsbury and Whittington, were in the hands of Paganel, Fitz-Alan, and William Peverel. Further south, the barons of Somerset were encouraged against him by William de Mohun from his hold at Dunster, strong naturally and by art; and by Fitz-John at Harptree, a castle in the defiles of the Mendips; while Maminot both held and strongly augmented Dover. Stephen, however, was active and he was brave. Leaving Archbishop Thurstan to muster and encourage his northern supporters, he himself marched south, strengthened the garrison of Bath, and threatened Bristol. Thence he entered Somerset, and took by siege the Lovel seat of Castle Cary, of which the earthworks cover a hillside; secured Harptree by surprise, and thence doubled back upon Hereford, which won, he next recovered the old British and English fortress of Pengwern or Shrewsbury. Bristol alone held out, strong in its newly-built keep, and in the presence of Robert Earl of Gloucester, its builder.