Second Barons' War: Battle of Evesham - the army of Prince Edward (the future king Edward I of England) defeats the forces of rebellious barons led by Simon de Montfort, 6th Earl of Leicester, killing de Montfort and many of his allies. 750 years.
British Prime Minister Winston Churchill makes the fourth of his famous wartime speeches, containing the line "Never was so much owed by so many to so few". 75 years.