Battle of Lewes - 1264

One of the two main battles during the Second Barons’ War, the Battle of Lewes made Simon de Montfort the ‘uncrowned King of England’.

What lead to war, was King Henry III - and his awful attitude. Ruling in an autocratic style, he gave vast displays of favouritism and out-right refused to negotiate with the barons. Eventually, the barons had enough, and imposed a constitutional reform - the Provisions of Oxford - which called upon the King to attend a thrice-yearly meeting with the barons (led by Simon of Montfort) to discuss matters of government.

But of course, King Henry didn’t want to attend the meetings (and the various restrictions that came along with it), and applied to King Louis IX of France to arbitrate the dispute. Louis sided with Henry (possibly because he didn’t want his own nobles getting similar ideas?), and annulled the provisions, leading to the War.