The history of Normandy is defined by three major stages: the Viking settlement that gave it its name, the medieval expansion with the conquest of England and the crucial role it played in the liberation of Europe during the Second World War. Origins and the Birth of the Duchy (911) • Ancient peoples: Inhabited by Celtic tribes and conquered by the Romans in the first century BC. • Arrival of the Vikings: The attacks of the Normans (men of the north) weakened the Frankish kings. • Treaty of Saint-Clair-sur-Epte (911): King Charles the Simple ceded the territory to the Viking leader Rollon. • Creation of Normandy: The Vikings converted to Christianity, adopted French culture, and founded the Duchy of Normandy. Medieval Normandy and the Conquest of England (1066) • William the Conqueror: In 1066, Duke William crossed the English Channel and defeated the Anglo-Saxons at the Battle of Hastings. • Temporary union: William was crowned king of England, uniting the destinies of both territories. • Integration into France (1204): King Philip II of France conquered the mainland region of Normandy, incorporating it into the French crown. The Channel Islands (such as Jersey and Guernsey) remained under British sovereignty. World War II and D-Day (1944) • Nazi occupation: During World War II, Normandy suffered German occupation. • Operation Overlord (June 6, 1944): The largest amphibious landing in history was executed. • D-Day: More than 150,000 Allied troops (American, British, and Canadian) crossed the English Channel to storm the Normandy beaches (Utah, Omaha, Gold, Juno, and Sword). • Liberation: After months of bloody fighting (Battle of Normandy), the Allies managed to open the Western Front that led to the defeat of Nazi Germany.