The Duchy of Normandy was a historical region in northern France that emerged in the 10th century. It was established when Viking leader Rollo was granted land by the French king in exchange for protection against further Viking raids. The duchy became a powerful feudal state, known for its strong military and economic influence. Normandy played a significant role in European history, particularly during the Norman Conquest of England in 1066, when William the Conqueror, the Duke of Normandy, claimed the English throne. The duchy remained an important political entity until it was integrated into the French crown in the 13th century.