A duchy is a territory ruled by a duke or duchess. Some duchies are sovereign entities, but most are subordinate districts of kingdoms.
Traditionally, a grand duchy, such as Luxembourg, was generally independent and sovereign. Sovereign duchies were common in the Holy Roman Empire and German-speaking areas.
In France, a number of duchies existed in the medieval period. Queen Elizabeth II of the United Kingdom still holds the medieval French title of Duke of Normandy; the only lands still attached to the Duchy of Normandy are the Channel Islands, and there no longer is a King of France to grant the title, but it is inherited regardless. Other important French duchies included Burgundy, Brittany, and Aquitaine.