Vikings invaded present-day Normandy in the 9th century, and some of them soon established settlements and adopted Christianity. In 911 French king Charles the Simple, of the Carolingian dynasty, and Viking chief Hrölfr agreed that the area around Rouen should be handed over to these Norsemen – or Normans, as they came to be known.
Throughout the Hundred Years War (1337–1453), the Duchy of Normandy seesawed between French and English rule. England dominated the region for some 30 years until France gained permanent control in 1450. In the 16th century, Normandy, a Protestant stronghold, was the scene of considerable fighting between Catholics and Huguenots.
More recently, the liberation of Western Europe from Nazi occupation began in earnest on the beaches of Normandy on D-Day, 6 June 1944. Much of Normandy was badly damaged during the fighting; the city of Le Havre, for example, was heavily bombed during the Allied bombing raids known as Operation Astonia in September 1944, resulting in over 2000 civilian deaths in that town alone.