 Simon de Montfort claimed to be ruling in the King 's name through a council of officials . However , he had effective political control over the government even though he was not himself the monarch , the first time this had happened in English history . Montfort successfully held a parliament in London in June 1264 to confirm new constitutional arrangements for England ; four knights were summoned from each county , chosen by the county court , and were allowed to comment on general matters of state – the first time this had occurred . Montfort was unable to consolidate his victory at Lewes , however , and widespread disorder persisted across the country . In France , Eleanor made plans for an invasion of England with the support of Louis . 
