ert ▁de ▁Burg h ▁John ▁expressed ▁his ▁fr ustration ▁towards ▁Lang ton , ▁calling ▁him ▁" a ▁not orious ▁tra itor ▁to ▁us , ▁since ▁he ▁did ▁not ▁render ▁our ▁castle ▁of ▁Ro chester ▁to ▁us ▁in ▁our ▁so ▁great ▁need ". ▁After ▁this ▁point , ▁Ro chester ▁Castle ▁was ▁no ▁longer ▁considered ▁to ▁be ▁in ▁the ▁perpet ual ▁cust ody ▁of ▁the ▁arch b ish ops ▁of ▁Can ter bury . ▁ ▁At ▁the ▁time , ▁John ▁was ▁in ▁south - east ▁England ▁rec ruit ing ▁mer cen aries ▁in ▁prepar ation ▁for ▁his ▁war ▁with ▁the ▁bar ons . ▁Ro chester ▁blocked ▁the ▁direct ▁route ▁to ▁London , ▁which ▁was ▁also ▁held ▁by ▁the ▁reb els . ▁According ▁to ▁Roger ▁of ▁Wend over , ▁the ▁reb els ▁at ▁Ro chester ▁were ▁led ▁by ▁William ▁d ' A ub igny , ▁lord ▁of ▁Bel voir . ▁Est im ates ▁of ▁the ▁size ▁of ▁Ro chester ' s ▁g arrison ▁vary , ▁with ▁the ▁chron ic lers ' ▁figures ▁r anging ▁from ▁ 9 5 ▁to ▁ 1 4 0   kn ights , ▁supported ▁by ▁cross bow men , ▁ser ge ants , ▁and ▁others . ▁H ear ing ▁the ▁news ▁that ▁the ▁city ▁was ▁in ▁enemy ▁hands , ▁John ▁immediately ▁rode ▁to ▁Ro chester ▁and ▁arrived ▁on ▁ 1 3 ▁October . ▁Royal ▁forces ▁had ▁arrived ▁ahead ▁of ▁John ▁and ▁entered ▁the ▁city ▁on ▁ 1 1 ▁October , ▁taking ▁it ▁by ▁surprise ▁and ▁lay ing ▁sie ge ▁to ▁the ▁castle