Governor of Gascony, a mistake that cost Henry dearly.
In Gascony, Montfort was disliked, but he was powerful and he abused his position and this forced Henry to intervene.
On Montfort's return to England, he perceived Henry as weak and with the barons aching for a fight, it was
Simon de Montfort that stepped in to take charge.
In 1258 this action culminated in the Provisions of Oxford, a law that served to limit Henry’s power. Henry’s refusal
to accept the Provisions of Westminster the following year saw Montfort’s power base grow rapidly, and by 1263 he
was all but wearing the crown.
On the 14th of May 1264 at the Battle of Lewes, Henry, his son the future Edward I, and Richard, Duke of Cornwall
were taken prisoner but a year later the tables were turned, and it was at the Battle of Evesham, on the 4th August in
1265, that Simon de Montfort and his eldest son Henry died a grisly death.
"My beloved child, both you and your father will meet your deaths on one day, and by one kind of death, but it
will be in the name of justice and truth."
The bishop was right on both counts:
Of Henry de Montfort's death, the
"first born son and heir, in full view of his father, perished, split by a sword.
and Simon himself:
"the head was severed from his body, and his testicles cut off and hung on either side of his nose"