 The parliament bought temporary calm but opposition grew once more , particularly as Montfort and his immediate family began to amass a huge personal fortune . Prince Edward escaped his captors in May and formed a new army , resulting in a fresh outbreak of civil war . Edward pursued Monfort 's forces through the Welsh Marches , before striking east to attack his fortress at Kenilworth and then turning once more on the rebel leader himself . Montfort , accompanied by the captive Henry , was unable to retreat and the Battle of Evesham ensued . Edward was triumphant and Montfort 's corpse was mutilated by the victors . In places the now leaderless rebellion dragged on , with some rebels gathering at Kenilworth , which Henry and Edward took after a long siege in 1266 . The remaining pockets of resistance were mopped up , and the final rebels , holed up on the Isle of Ely , surrendered in July 1267 , marking the end of the war . 
