Barons' War

Civil war begun by the English barons under Simon de Montfort (the Younger), leader of a reform movement against King Henry III of England's government. Success at the Battle of Lewes in 1264 led to the king's capture, but at the Battle of Evesham in 1265 the rebellious barons were brutally massacred.

The Montfortians' power base was around Kenilworth Castle, Warwickshire. Marching south, Simon challenged the royalists outside Lewes in Sussex on 14 May. Despite a successful charge by Prince Edward, the royalists were routed by Simon's tactics and Henry was captured.

Deserted by some of his allies, who changed sides in 1265, Simon was outmanoeuvred and drawn into a killing ground at Evesham, where he was killed, along with many other rebel barons. Montfortian castles continued to hold out until 1267. Kenilworth, surrounded by sophisticated water defences, withstood six months' intense siege until forced to surrender in December 1266.