As an historian who has devoted 35 years to the study of 13th century documents relating to Simon de Montfort I would like to take part in this debate.
Simon de Montfort expelled the Jews of Leicester in 1231. It was in his youth and he was not yet Earl of Leicester. He found himself effectively leader of a mob attacking the Jews for their high interest rates in money lending. Montfort’s dealings with the Jews of Leicester were not on religious but on fiscal grounds. His spiritual advisor, Bishop Robert Grosseteste who was a friend of Jews and a scholar of Hebrew, had just established a home in London for displaced Jews; was there an element of his influence? In any case, high interest rates were a life-long concern of Montfort’s, not antisemitism. In 1238 he was excommunicated for refusing to pay an inflated interest rate,
See Annales Monastici, ed. H.R. Luard, vol. IV, Chronicon Thomas Wykes, p.148 and Annales Prioratus de Wigorna, (Worcester) p. 448 for Leicester. For excommunication debt see Archivesde la Chambre de comptes Lille, no. 671, p. 270 and Royal Letters, vol. II, p. 16.
Later in life Montfort quelled the riot against the Jews of London (1264) although he had been out of the city on his way to rescue his own son Simon who had been captured by King Henry’s forces. It was Montfort’s commoner partisans in London who attacked the Jews. Montfort was forced to remain in London, abandoning his battle plan in defense of Parliament in order to protect the Jews. At last he was forced to take the London mob with him to attack Rochester in his effort to keep the royalists from bringing in foreign troops to destroy Parliament.
At Rochester, the mob of Londoners stole, raped and murdered the people of Rochester, including using the monk bell ringer of the cathedral for archery practice. Montfort withdrew his knights from combat and had them arrest all the Londoners found committing crimes. The following day, within view of the royalist forces, he had all those Londoners beheaded. The remainder of this rabble he placed opposite Prince Edward in the battle at Lewes where they were chased and slaughtered by the Prince.
Thus were the attackers of Jews treated by Simon de Montfort.
See Wykes, Annales, vol IV, pp. 140-1 and Annales of Dunstable, vol. III, p. 230 (London Jews; Flores Historiarum, p. 490, Chronicon de Bellis, Thomas Rishanger, p. 25 and Wykes, p. 146 for Rochester. For Battle of Lewes see Charles Oman, History of the Art of War in the Middle Ages, vol. I, pp. 424-30 and map.
At Rochester these same people who had attacked the Jews attacked the citizens of Rochester. Montfort had them seized and beheaded publicly at the foot of Rochester’s still royalist-held castle. His establishment of Parliament, the model of all further democracies, is far more significant than his early participation as the most readily identifiable person in a riot that drove the community of Jewish money lenders from Leicester.