The reaction against Montfort’s government is baronial…
1265 CE
The reaction against Montfort’s government is baronial rather than popular.
The Welsh Marcher Lords are friends and allies of Edward, and they rally around his opposition in May 1265 when he escapes.
The final nail is the defection of the most powerful baron and Simon's ally at Lewes, Gilbert de Clare, the earl of Gloucester, who has grown resentful of Simon's fame and growing power.
When he and his brother Thomas fall out with Simon's sons Henry, Simon and Guy, he deserts the reforming cause and joins Edward.
Though boosted by Welsh infantry sent by Montfort's ally Llywelyn, Simon's forces are severely depleted.
Lord Edward attacks his son Simon's forces at Kenilworth, capturing more of Montfort's allies.
Gilbert de Clare, having changed sides, shares the Prince's victory on July 16 at Kenilworth.