The First Barons' War caused significant destruction to Northampton. The barons besieged Northampton Castle in protest at King John's oppression of his subjects. In retaliation, royalist forces destroyed a large part of the town. When the forces of King Henry III overran the supporters of Simon de Montfort, the Second Barons' War broke out. The First Battle of Northampton took place in 1264 at the site of Northampton Castle where King Henry III and his son Prince Edward attacked with a large army, pillaged the town and took prisoners.