When was the Hundred Years War and who fought in it?
The English and French fought from the mid-14th century well into the 15th century. The English king reigned over not only the British islands but in Normandy, France. (Read up on William the Conqueror for the story of how that came to be.) The result of this continental foothold meant that the English fought mostly in France, from Brittany to the south of France, and east towards Flanders.

Fighting in this time was particularly brutal. "Men at Arms" were knights, wearing full suits of armor. Supporting these Men at Arms were crossbowman (on the French side) and archers, using the English War Bow, on the English side. The War Bow was an extremely powerful weapon.