▁military ▁historian ▁C ath cart ▁King ▁notes ▁that ▁they ▁seem ▁to ▁have ▁been ▁pre domin antly ▁high - status ▁cast les . ▁Ro chester ' s ▁castle - guard ▁consisted ▁of ▁ 6 0   kn ights ' ▁fe es , ▁mark ing ▁it ▁as ▁a ▁particularly ▁important ▁fort ification . ▁ ▁It ▁was ▁probably ▁William ▁the ▁Con quer or ▁who ▁gave ▁the ▁city ▁and ▁its ▁castle ▁to ▁Bishop ▁O do ▁of ▁Bay e ux , ▁the ▁king ' s ▁half ▁brother . ▁On ▁William ' s ▁death ▁in ▁September ▁ 1 0 8 7 ▁his ▁territ ories ▁were ▁divided ▁between ▁his ▁two ▁sons . ▁Robert , ▁the ▁elder , ▁inherited ▁the ▁title ▁of ▁Duke ▁of ▁Norm andy ▁and ▁William ▁R uf us ▁became ▁King ▁of ▁England . ▁A ▁significant ▁number ▁of ▁Norman ▁bar ons ▁object ed ▁to ▁div iding ▁Norm andy ▁and ▁England , ▁and ▁Bishop ▁O do ▁supported ▁Robert ' s ▁claim ▁to ▁the ▁English ▁throne . ▁Several ▁others , ▁including ▁the ▁ear ls ▁of ▁North umber land ▁and ▁Sh rew s bury ▁and ▁the ▁Bishop ▁of ▁C out ances ▁came ▁out ▁in ▁support ▁of ▁Robert . ▁O do ▁prepared ▁Ro chester ▁Castle ▁for ▁war ▁and ▁it ▁became ▁one ▁of ▁the ▁headquarters ▁of ▁the ▁re bell ion . ▁Its ▁position ▁in ▁Kent ▁made ▁it ▁a ▁suitable ▁base ▁for ▁ra ids ▁on ▁London ▁and ▁its ▁g arrison ▁could ▁har ry ▁William ' s ▁forces ▁in ▁the ▁county . ▁William ▁set ▁off ▁from ▁London ▁and ▁march ed ▁towards ▁Ro chester ▁to ▁deal ▁with