The Battle of Lewes was one of two main battles of the conflict known as the Second Barons' War. It took place at Lewes in Sussex, on 14 May 1264. It marked the high point of the career of Simon de Montfort, 6th Earl of Leicester, and made him the "uncrowned King of England". The battle occurred because of the vacillation of King Henry III, who was refusing to honour the terms of the Provisions of Oxford, an agreement he had signed with his barons, led by Montfort, in 1258. Prince Edward (later King Edward I) commanded the cavalry.