Siege of Château Gaillard
1203 CE.
Shown on the map at 49.238°, 1.403°.
The siege of Château Gaillard was a part of the campaign of King Philip II of France to conquer Normandy from King John of England. The French king besieged Château Gaillard, a Norman fortress, for six months. The Anglo-Normans were beaten in the battle and the consequence was the fall of Normandy. The fortress was notable for having been a very technologically advanced castle at the time it was built, having several notable features in its construction such as having notably thick walls ranging from 2.5 to 3.5 meters in thickness and the first stone machicoulis ever constructed within France.
Text from the Wikipedia article Siege of Château Gaillard, licensed CC BY-SA 4.0.