However, he was weakened the next year by the machinations of Richard de Clare and the negative views of his alliance with Llewellyn.
The papal legate Ottobon urged moderation in dealing with the supporters of this man, whose death led to those supporters pillaging the countryside from strongholds at places like Axholme and Ely. He had first consolidated his power after using his brightly decorated litter as a trap in battle and by raising a fleet in the Cinque Ports.  He would then briefly establish co-rule with the Bishop of Chichester and the Earl of Gloucester. However, he was weakened the next year by the machinations of Richard de Clare and the negative views of his alliance with Llewellyn. His end came when his son was defeated at Kenilworth and when his own forces fell the next day at Evesham. For 10 points, name this French-English nobleman who briefly ruled England after the Barons' War of 1263
The papal legate Ottobon urged moderation in dealing with the supporters of this man, whose death led to those supporters pillaging the countryside from strongholds at places like Axholme and Ely.
Simon de Montfort, 6th Earl of Leicester