 In response , and hoping to win wider support for his government , Montfort summoned a new parliament for 20 January 1265 which continued until mid March that year . It was held at short notice , with the summons being issued on 14 December , leaving little time for attendees to respond . He summoned not only the barons , senior churchmen and two knights from each county , but also two burgesses from each of the major towns such as York , Lincoln , Sandwich , and the <unk> Ports , the first time this had been done . Due to the lack of support for Montfort among the barons , only 23 of them were summoned to parliament , in comparison to the summons issued to 120 churchmen , who largely supported the new government ; it is unknown how many burgesses were called . The event was overseen by King Henry , and held in the Palace of Westminster , London , which was the largest city in England , and whose continuing loyalty was essential to Montfort 's cause . 
