, ▁which ▁later ▁became ▁known ▁as ▁Mag na ▁Cart a , ▁was ▁se aled . ▁Short ly ▁after ▁the ▁treat y ▁the ▁agreement ▁between ▁John ▁and ▁Lang ton ▁to ▁appoint ▁a ▁royal ▁const able ▁in ▁charge ▁of ▁Ro chester ▁Castle ▁was ▁dissol ved , ▁returning ▁control ▁to ▁the ▁arch bishop . ▁The ▁peace ▁did ▁not ▁last ▁and ▁the ▁First ▁Bar ons ' ▁War ▁broke ▁out . ▁A ▁group ▁of ▁reb els ▁head ed ▁to ▁Ro chester ▁to ▁hold ▁the ▁city ▁against ▁John . ▁The ▁events ▁surrounding ▁the ▁reb els ' ▁take over ▁of ▁the ▁castle ▁are ▁unclear , ▁but ▁contemporary ▁chron ic ler ▁Ralph ▁of ▁C og ges hall ▁recorded ▁that ▁the ▁king ▁demanded ▁Lang ton ▁hand ▁over ▁the ▁castle ▁to ▁royal ▁control ▁and ▁the ▁arch bishop ▁refused . ▁Lang ton ▁held ▁out ▁against ▁the ▁king ' s ▁dem ands , ▁but ▁the ▁reb els ▁fe ared ▁he ▁would ▁eventually ▁cave ▁to ▁pressure ▁from ▁the ▁king ▁and ▁seized ▁control ▁of ▁Ro chester ▁Castle ▁for ▁themselves . ▁According ▁to ▁Ralph ▁of ▁C og ges hall , ▁this ▁was ▁done ▁with ▁the ▁consent ▁of ▁the ▁castle ' s ▁const able , ▁Regin ald ▁de ▁Corn hill , ▁who ▁seems ▁to ▁have ▁switched ▁alleg iance ▁from ▁the ▁king ▁to ▁the ▁arch bishop ▁after ▁John ▁appointed ▁him ▁as ▁royal ▁const able ▁of ▁the ▁castle . ▁Lang ton ▁left ▁the ▁country ▁that ▁same ▁month , ▁leaving ▁the ▁castle ▁in ▁the ▁hands ▁of ▁the ▁king ' s ▁enemies . ▁In ▁a ▁letter ▁that ▁year ▁to ▁just ici ar ▁Hub