  III ' s ▁reign ▁was ▁in ▁crisis ▁in ▁ 1 2 5 8 . ▁He ▁had ▁recently ▁suffered ▁defeat ▁in ▁Wales , ▁there ▁were ▁agricult ural ▁problems ▁leading ▁to ▁a ▁fam ine , ▁and ▁relations ▁with ▁the ▁po pe ▁were ▁w ors ening . ▁Dis content ▁amongst ▁England ' s ▁magn ates ▁led ▁Henry ▁to ▁promise ▁reform , ▁but ▁under ▁continued ▁pressure ▁his ▁authority ▁dis integr ated . ▁A ▁royal ▁council ▁of ▁fifteen ▁magn ates ▁was ▁formed ▁in ▁June ▁that ▁year , ▁and ▁the ▁rule ▁of ▁the ▁country ▁transferred ▁from ▁the ▁king ▁to ▁the ▁council . ▁With ▁foreign ▁help ▁Henry ' s ▁reign ▁was ▁restored ▁in ▁ 1 2 6 1 ▁as ▁the ▁council ▁were ▁rel uct ant ▁to ▁start ▁a ▁civil ▁war . ▁Simon ▁de ▁Mont fort , ▁Earl ▁of ▁Le ic ester , ▁raised ▁a ▁re bell ion . ▁In ▁ 1 2 6 4 ▁civil ▁war ▁broke ▁out ▁between ▁those ▁loyal ▁to ▁the ▁king ▁and ▁the ▁bar onial ▁forces ▁led ▁by ▁de ▁Mont fort . ▁ ▁Ro chester ' s ▁const able ▁in ▁ 1 2 6 4 , ▁Roger ▁de ▁Ley bourne , ▁held ▁the ▁castle ▁in ▁support ▁of ▁Henry . ▁John ▁de ▁War enne , ▁Earl ▁of ▁Sur rey , ▁was ▁the ▁g arrison ' s ▁co - comm ander . ▁A ▁bar onial ▁army ▁led ▁by ▁Gilbert ▁de ▁Cla re , ▁Earl ▁of ▁H ert ford , ▁laid ▁sie ge ▁to ▁the ▁castle ▁on ▁ 1 7 ▁April ▁that ▁year . ▁Having ▁march ed ▁from ▁the