(c.1208–65) Became Earl of Leicester. Married Eleanor, sister of Henry III in 1238. Leader of barons’ revolt against the King, whom he defeated in 1264 at the Battle of Lewes. Defeated by royal forces, including Marcher lord, at the Battle of Evesham 1265. Llywelyn ap Gruffudd married Simon de Montfort’s daughter, Eleanor, in 1278.