Short answers, pulled from the story.
Rollo and Charles the Simple signed the Treaty of Saint-Clair-sur-Epte in 911 to establish the Duchy of Normandy. This agreement granted Rouen and present-day Upper Normandy to Rollo following his victory over Robert I at the Battle of Chartres.
Archaeologists discovered objects such as the Gallic gilded helmet of Amfreville-sous-les-Monts made in the 4th century BC. Excavations at Pîtres revealed a cemetery with urns for cremated remains indicating Hallstatt culture activity alongside La Tène culture marks.
Louis XI forced nobles to cede the duchy to his brother Charles in 1465 and agreed to exchange Normandy for Guyenne on the 9th of November 1469. The region was definitively integrated into the Kingdom of France in 1204 after suffering significant damage during the war.
Allied Britain U.S Canada coordinated massive build-up troops supplies support large-scale invasion Normandy D-Day landings the 6th of June 1944. Germans dug fortified emplacements above beaches Caen Cherbourg Carentan Falaise towns endured many casualties until liberation Le Havre followed significant turning point war restoration French Republic remainder Normandy liberated the 9th of May 1945 end war Occupation Channel Islands effectively ended.
Agriculture remained important industries weaving metallurgy sugar refining ceramics shipbuilding introduced developed 18th century. Economic revival mechanization textile manufacture first trains occurred after Revolutionary Napoleonic Wars 1792-1815 leading to seaside tourism birth first beach resorts 19th century marks beginning coastal development era.