In 1149, York opened its gates to young Henry of Anjou, who assembled a considerable force, with which he met the royal army at Malmesbury, though without an actual collision. Of 1151 is on record a curious convention in which the Earls of Leicester and Chester were concerned, under which no new castles were to be built between Hinckley and Coventry, Coventry and Donnington, Donnington and Leicester; nor at Gateham, nor at Kinoulton, nor between Kinoulton and Belvoir, Belvoir and Oakham, Oakham and Rockingham. In 1152 occurred the celebrated siege of Wallingford, held for Matilda by Brian Fitz-Count. Enough of Wallingford remains to show how strong it must formerly have been; and the temporal was fully equalled by the spiritual power, for the town, always small, contained just twice as many churches as apostolic Asia. Stephen, unable to approach the Castle from its landward side, threw up a work still to be traced at Crowmarsh, on the left bank of the river, and there posted his engines. Young Henry, holding Malmesbury, Warwick, and about thirty other not very distant castles, marched to the relief of Wallingford, and invested the lines of Crowmarsh, besieging the besiegers. Stephen advanced to their aid from London, and Henry seems to have moved into the town, holding the passage of the river at the bridge by a special work. Wallingford was thus saved, and Henry, early in 1153, laid siege to Stamford, where, as at York, Hertford, and Buckingham, two mounds commanded the river; and stormed Nottingham, where were similar works upon the Trent. Stephen, falling back into the eastern counties, took Ipswich, a castle of which even the site is lost.