The title "Duke of Normandy" refers to the ruler of the historical region of Normandy in northern France. Established in the 10th century, the duchy was created when the Viking leader Rollo was granted land by the French king in exchange for his loyalty and protection against other Viking raids. The Dukes of Normandy played a significant role in the political landscape of medieval Europe. One of the most famous Dukes was William the Conqueror, who became the first Norman king of England after his successful invasion in 1066. The title continued to hold importance until the French crown absorbed Normandy in the 13th century, marking the end of the duchy's independence.