French King Philip VI's Great Council in Paris formally confiscates the Duchy of Aquitaine (Gascony) on May 24, 1337, taking away King Edward III lands in France.
In response, Edward III sent a formal challenge to Philip VI and began using documents that implied his claim to the French throne, creating the "trigger cause" and marking the start of the hostilities and the start of the Hundred Years' War. This was followed on January 26, 1940 with a full public proclamation declaring himself King of France, in part to provide legal cover for his alliance with the Flemish. The 100 year War was eventually won by the French at the Battle of Castillon in 1453.
