The reaction against Montfort's government was baronial rather than popular.
The Welsh Marcher Lords were friends and allies of Prince Edward, and when he escaped in May 1265, they rallied around his opposition.
The final nail was the defection of Gilbert de Clare, the Earl of Gloucester, the most powerful baron and Simon's ally at Lewes.
Clare had grown resentful of Simon's fame and growing power.
When he and his brother Thomas fell out with Simon's sons Henry, Simon the Younger, and Guy, they deserted the reforming cause and joined Edward.

Though boosted by Welsh infantry sent by Montfort's ally Llywelyn ap Gruffudd, Simon's forces were severely depleted.
Prince Edward attacked his cousin, his godfather's son Simon's forces at Kenilworth, capturing more of Montfort's allies.
Montfort himself had crossed the Severn with his army, intending to rendezvous with his son Simon the Younger.
When he saw an army approaching at Evesham, Montfort initially thought it was his son's forces.
It was, however, Edward's army flying the Montfort banners they had captured at Kenilworth.
At that point, Simon realised he had been out-manoeuvred by Edward.

An ominous black cloud hung over the field of Evesham on 4 August 1265 as Montfort led his army in a desperate uphill charge against superior forces, described by one chronicler as the "murder of Evesham, for battle it was none".
On hearing that his son Henry had been killed, Montfort replied, "Then it is time to die."
During the battle, a twelve-man squad of Edward's men had stalked the battlefield independent of Edward's main army, their sole aim being to find the earl and cut him down.
Montfort was hemmed in; Roger Mortimer killed Montfort by stabbing him in the neck with a lance.
Montfort's last words were said to have been "Thank God".
Also slain with Montfort were other leaders of his movement, including Peter de Montfort and Hugh Despenser.

Montfort's body was mutilated in a frenzy by the royalists.
News reached the mayor and sheriffs of London that "the head of the earl of Leicester ... was severed from his body, and his testicles cut off and hung on either side of his nose"; and in such guise the head was sent to Wigmore Castle by Roger Mortimer, 1st Baron Mortimer, as a gift to his wife, Maud.
His hands and feet were also cut off and sent to diverse places to enemies of his as a great mark of dishonour to the deceased.
Such remains as could be found were buried before the altar of Evesham Abbey church by the canons.
The grave was visited as holy ground by many commoners until King Henry caught wind of it.
He declared that Montfort deserved no spot on holy ground, and had his remains reburied in another "secret" location, probably in the crypt.
The remains of some of Montfort's soldiers who had fled the battlefield were found in the nearby village of Cleeve Prior.

Montfort's niece, Margaret of England, later killed one of the soldiers responsible for his death, purposely or inadvertently.

Matthew Paris reports that the Bishop of Lincoln, Robert Grosseteste, once said to Montfort's eldest son, Henry, "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 reaction against Montfort's government was baronial rather than popular. The Welsh Marcher Lords were friends and allies of Prince Edward, and when he escaped in May 1265, they rallied around his opposition. The final nail was the defection of Gilbert de Clare, the Earl of Gloucester, the most powerful baron and Simon's ally at Lewes. Clare had grown resentful of Simon's fame and growing power. When he and his brother Thomas fell out with Simon's sons Henry, Simon the Younger, and Guy, they deserted the reforming cause and joined Edward.
Though boosted by Welsh infantry sent by Montfort's ally Llywelyn ap Gruffudd, Simon's forces were severely depleted. Prince Edward attacked his cousin, his godfather's son Simon's forces at Kenilworth, capturing more of Montfort's allies. Montfort himself had crossed the Severn with his army, intending to rendezvous with his son Simon the Younger. When he saw an army approaching at Evesham, Montfort initially thought it was his son's forces. It was, however, Edward's army flying the Montfort banners they had captured at Kenilworth. At that point, Simon realised he had been out-manoeuvred by Edward.
An ominous black cloud hung over the field of Evesham on 4 August 1265 as Montfort led his army in a desperate uphill charge against superior forces, described by one chronicler as the "murder of Evesham, for battle it was none". On hearing that his son Henry had been killed, Montfort replied, "Then it is time to die." During the battle, a twelve-man squad of Edward's men had stalked the battlefield independent of Edward's main army, their sole aim being to find the earl and cut him down. Montfort was hemmed in; Roger Mortimer killed Montfort by stabbing him in the neck with a lance. Montfort's last words were said to have been "Thank God". Also slain with Montfort were other leaders of his movement, including Peter de Montfort and Hugh Despenser.
Montfort's body was mutilated in a frenzy by the royalists. News reached the mayor and sheriffs of London that "the head of the earl of Leicester ... was severed from his body, and his testicles cut off and hung on either side of his nose"; and in such guise the head was sent to Wigmore Castle by Roger Mortimer, 1st Baron Mortimer, as a gift to his wife, Maud. His hands and feet were also cut off and sent to diverse places to enemies of his as a great mark of dishonour to the deceased. Such remains as could be found were buried before the altar of Evesham Abbey church by the canons. The grave was visited as holy ground by many commoners until King Henry caught wind of it. He declared that Montfort deserved no spot on holy ground, and had his remains reburied in another "secret" location, probably in the crypt. The remains of some of Montfort's soldiers who had fled the battlefield were found in the nearby village of Cleeve Prior.
Montfort's niece, Margaret of England, later killed one of the soldiers responsible for his death, purposely or inadvertently.
Matthew Paris reports that the Bishop of Lincoln, Robert Grosseteste, once said to Montfort's eldest son, Henry, "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."
Simon de Montfort, 6th Earl of Leicester