Simon de Montfort, the father was in fact Simon IV de Montfort (1160-1218), a Norman knight who took part in the Fourth Crusade in 1202-1204 and was prominent in the Albigensian Crusade. He died at the siege of Toulouse in 1218.
Simon de Montfort, son of the above, was born in 1208. In 1230, he tried his fortunes in England, where, in 1238, he secretly married Eleanor, sister of King Henry III of England. Eleanor had previously been married to William Marshal, Earl of Pembroke, and had sworn a vow of chastity on his death, which she broke by marrying Simon. Once reconciled to the match, the king created Simon Earl of Leicester, but they frequently disagreed.
Like his father, Simon was a hardened and ruthless soldier, as well as a capable administrator. The main cause of his dispute with the king was the latter's determination to ignore the swelling discontent within the country, caused by a combination of factors which included famine. In 1258, at Oxford, Simon was instrumental in calling a parliament which is regarded as the forerunner of the modern institution. The king's son, the future King Edward I of England was at first sympathetic to Simon's cause, but later they became enemies, and the Provisions of Oxford, which the king had sworn to uphold, were broken at the behest of the Pope in 1261.
Civil war broke out, and Simon de Montfort's army met and defeated the royal forces at the Battle of Lewes in 1264. Prince Edward was taken prisoner, and the subsequent treaty set up a model parliament to agree a constitution formulated by Simon. However, his many enemies turned his triumph into disaster, and he was defeated and killed by Edward's forces during the Baron's War[?] at the Battle of Evesham in 1265, his body being mutilated, eviscerated and the remains scattered. His family were forced into exile in Simon's native France.
There is a memorial to Simon de Montfort in the park in Evesham in a place believed to be near where the High Altar of Evesham Abbey was located and a Stone Cross in the nearby Churchyard, the Stone Cross being viewable from the park. The memorial states that it is constructed with stone brought from near his birthplace in France.